-1 Has .9. arumm. .v'l - a, :.>uwr£ww.unfid. . ll Lnflfinflflfnmfl s. _ . 4 awaieflfss 9': IS! .5. a... t 1.1.... w! Aurel. ‘ u . 99...}. a. .u .vhizv-KLED ‘ it. ad. ér...ix.....tV 112.: 55.... I .li? 31.5. i I $.92 .1: fifitlfillt. £21.55! _._1 |u yarn LIBRARY " Mich ;, "tate Uriviar§jix____l This is to certify that the dissertation entitled DO LOCAL ROADS MATTER? LINKING LOCAL ROADS SPENDING TO DECENTRALIZATION IN THE DETROIT METROPOLITAN AREA presented by ANNALIE L. CAMPOS has been accepted towards fulfillment of the requirements for the Ph. D. degree in Geggraphy Major Professor’s Signature 5M7 25’9”; 2 0 o 2 Date MSU is an Affinnative Action/Equal Opportunity Employer PLACE IN RETURN BOX to remove this checkout from your record. To AVOID FINES return on or before date due. MAY BE RECALLED with earlier due date if requested. DATE DUE DATE DUE DATE DUE 5/08 K:IProj/Acc8Pres/ClRC/Date0ue.indd DO LOCAL ROADS MATTER? LINKING LOCAL ROADS SPENDING TO DECENTRALIZATION IN THE DETROIT METROPOLITAN AREA By Annalie L. Campos A DISSERTATION Submitted to Michigan State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Geography 2009 ABSTRACT DO LOCAL ROADS MATTER? LINKING LOCAL ROADS SPENDING TO DECENTRALIZATION IN THE DETROIT METROPOLITAN AREA By Annalie L. Campos The purpose of this dissertation research is to determine the causal relationship between local roads spending (i.e., state-allocated road spending and locally-raised road spending) and the decentralization of people in the context of the Detroit Metropolitan Area between 1980 and 1990. This research adopts a human ecology methodological framework and develops a conceptual model that broadly integrates local roads spending with proposed explanations of decentralization. The conceptual model is developed within social geographic inquiry and is informed by three perspectives (a) ecological and spatial assimilation, (b) neighborhood preference, and (0) place stratification in understanding the decentralization process. This research integrates each of these three proposed theoretical perspectives into the human ecological framework to conceptualize how local roads spending affected decentralization during that decade. A standard multiple regression and spatial regression approaches were implemented to estimate the effect of local road spending on decentralization. Three models were estimated using three different measures of decentralization as the dependent variable in these models, including: 1) percent change in general population density; 2) percent change in the relative concentration of non-whites; and 3) percent change in population density of non-whites. The first dependent variable measured the pattern of decentralization in the general population and the latter two dependent variables measured the non-whites’ pattern of decentralization. The dependent variables were each regressed against a lagged value of state- allocated road spending at the municipality level controlling for local road stock, distance from the central business district (i.e., downtown Detroit), household median income, percent college educated non-whites, percent of the non-white population, and proportion of white to total homeowners. The result from the first model (i.e., percent change in general population density) indicated that state-allocated road spending had a significant effect on decentralization (,8 = 0.56, p < 0.10). The result from the second model (i.e. the percent change in the relative concentration of non-whites) indicated that locally-raised road spending had a significant effect on decentralization (,B = 1.76, p <0.001). On the other hand, the results fiom the third model (i.e., percent change in population density of non-whites) did not indicate significance of either state-allocated or locally-raised local road spending on non-whites’ decentralization. Other variables that were important in all three models of decentralization were percent non-whites and distance from the central business district. These findings show that both state-allocated and locally-raised spending were important in decentralization in the Detroit Metropolitan Area but the populations impacted varied. While future research Should continue to investigate the effects of both spending on racial differences in decentralization, the study recommends an emphasis on the state-allocated road spending mechanism and its policy implications. To my husband Danny, and daughters Katrina, Micaela, and Leanna, my parents, and in memory of my grandmother, Romana iv ACKNOWLEDGEMENTS This dissertation is an outcome of collective efforts and I would like to recognize and thank many individuals here. First and foremost, I thank God who gave me the hope and strength in overcoming many hurdles with completing a dissertation. I am also greatly blessed for having a strong army of friends from the Fellowship of Christian Internationals and my family who never wavered in their support and encouragement. My committee had provided guidance and support in all dimensions of dissertation development and writing. I feel very fortunate to have had Dr. Ashton Shortridge for his objective comments and prompt attention to my dissertation needs. His patience and kindness throughout my graduate program are very much appreciated. I am thankful to Dr. Sue Grady for her concerns for my academic and personal well-being. Her guidance and support improved the content and structure of my dissertation. I would also like to thank Dr. John Schweitzer who inspired me to learn statistics and pursue research that matters and enjoyable. I am grateful for his, and Liz’s constant optimism and encouragement. Last but not least, I would like to thank Dr. Soji Adelaja for his leadership in my committee, support, and guidance. I admire his wisdom and spirit of innovation. I appreciate his generosity, both time and ideas, and attention to quality writing and research. I am indebted to my professors in geography as well as many others who have contributed to my personal and professional growth. 1 am grateful to Dr. Joe Darden for his guidance and encouragement. I benefited from our discussions, which improved my dissertation significantly. 1 will be always thankful to Dr. Bruce Pi gozzi who has an open door policy and willingness to listen and interact with students. I am grateful to Dr. Jay Harman as well for his support and words of wisdom. I am thankful for Drs. Catherine Yansa and Cynthia Simmons whose encouragement and fiiendship meant a lot to me as a woman geographer. I appreciate Dr. Antoinette Winklerprins for her support during my entire graduate program. Her advice and assistance in obtaining research and travel grants were invaluable. I am also thankful to Dr. Groop for his insights and advice. My deep appreciation goes to the staff in the geography department especially to Sharon Ruggles, Judy Reginek, and Wilson Ndovie for their friendship and assistance at different phases of my graduate program. My deep appreciation is for LuAnn Gloden at the Land Policy Institute for her assistance, encouragement, patience, and genuine friendship. I would not have been able to complete my graduate program without financial support. I am truly thankful to the Land Policy Institute, Urban Affairs Programs, Families and Communities Together (FACT), the Julian Samora Research Institute, and the Office of the University Outreach and Engagement. The research experience I gained from working in different projects in these organizations has been invaluable. The Geography Department and the College of Social Science have also provided assistantship, research and travel support, and a dissertation completion fellowship. I am truly grateful for these and many other kinds of support that the Department of Geography provided especially a work space, copying, and an office telephone, which added to my sense of security during those long nights. Many staff from the Michigan Department of Transportation provided assistance with data and interpretation of results. Ed Tricee, Mary C'umberworth, Richard Turcotte are very much appreciated. I also benefited from discussions with David Bertram of the vi Michigan Township Association, and Dr. Jim McConell who also provided me with comprehensive materials about the study region. Many friends and colleagues are truly like family. I thank Connie and Bob for being our wonderful parents in East Lansing, They have stood by us and our children as we juggled work, school, and parenting. I am grateful to Donna and Bob McKelvey, Rex and Vangie Alocilja and our fiiends at the Bible Study group. They have encouraged, inspired, laughed, and cried with me. I also appreciate Yohannes and Ahadu for their meaningful friendship, support, and encouragement. Dr. Dozier Thornton deserves a special recognition for his belief in what I can accomplish, financial and academic support, his wisdom, and friendship. My geography pals, past and present, have made graduate school fun and memorable. I especially thank Steve Aldrich, Ivan Ramirez, Eric Sandberg, Sarah Hession, and Rita Pereira who were always supportive and encouraging. They all made graduate school something to look back with a big smile. My deepest gratitude is to my husband Danny for the compromises he made so I can pursue and complete my program. I also thank my children for their understanding and cooperation. Lastly, I remain thankful in everything, for the joys and challenges that came along with this journey. vii TABLE OF CONTENTS LIST OF TABLES ............................................................................................................. xi LIST OF FIGURES .......................................................................................................... xii CHAPTER ONE: INTRODUCTION ................................................................................. 1 Background to the Study ............................................................................................ 1 An Overview of Causes of Decentralization in US Metropolitan Areas ............. 4 The Research Context and Questions ........................................................................ 6 Roads, Government Spending, and Decentralization ........................................ 10 Highway Development and Decentralization .................................................... 12 Local Roads and Decentralization ..................................................................... l4 Purpose of the Study ................................................................................................ 15 The Research Framework ........................................................................................ 16 Significance of the Study ......................................................................................... 18 CHAPTER TWO: RELEVANT LITERATURE ............................................................. 20 Decentralization in US Metropolitan Areas ............................................................. 21 Definition of Decentralization ........................................................................... 22 Theoretical Background ........................................................................................... 25 The Spatial Assimilation Perspective ................................................................ 27 Socioeconomic Status and Population Decentralization ........................... 29 The Place Stratification Perspective .................................................................. 33 Social Barriers to Population Decentralization ......................................... 33 Discrimination in Housing ........................................................................ 37 The Neighborhood Preference Perspective ........................................................ 40 Preference for Homogeneous versus Integrated Neighborhood ............... 40 The Role of Government Policy in Population Decentralization ............................ 42 Government Policy on Roads and Decentralization .......................................... 42 Potential Links between Local Roads and Decentralization .............................. 45 Summary .................................................................................................................. 49 CHAPTER THREE: THE CONCEPTUAL MODEL ...................................................... 51 The Human Ecology Framework ............................................................................. 52 Sociological Interpretations of Human Ecology ................................................ 53 The Classic Ecological Models ................................................................. 54 Human Ecology within Geographic Inquiry ...................................................... 58 Understanding Patterns of Decentralization using a Human Ecology Framework ............................................................................................................... 61 The Conceptual Model ............................................................................................. 62 Hypotheses of the Study .......................................................................................... 69 CHAPTER FOUR: THE EMPIRICAL MODEL ............................................................. 71 Model Specification ................................................................................................. 72 viii Specific Aims ........................................................................................................... 76 CHAPTER FIVE: DATA AND METHODS ................................................................... 78 The Study Area ........................................................................................................ 78 General Considerations for Selecting the Case Study Area ............................... 81 Regional Population Trends ...................................................................... 82 Land Use Change and Pattern of Uneven Development .......................... 84 Income Disparity ....................................................................................... 85 Racial Segregation .................................................................................... 86 Job Distribution ......................................................................................... 87 The Study Period and Communities .................................................................. 88 The Unit of Analysis and Observation ............................................................... 89 The Dependent Variable .................................................................................... 91 Population Decentralization ...................................................................... 91 The Independent Variables ................................................................................ 95 Local Roads Spending and Stock ............................................................. 95 Income and Education ............................................................................. 100 Proportion of White Homeowners .......................................................... 102 Percent Non-white Population ................................................................ 103 Distance from the Central Business District ........................................... 104 Data and Data Selection ......................................................................................... 105 Data Collection and Processing ....................................................................... 105 The Database .................................................................................................... 106 Empirical Model Estimation .................................................................................. 108 Ordinary Least Squares .................................................................................... 109 Variable Transformation ......................................................................... 1 10 Spatial Lag Model ............................................................................................ 11 1 Summary of Data and Estimation Procedure ......................................................... 113 CHAPTER SIX: RESULTS AND DISCUSSION ......................................................... 114 Descriptive Characteristics of the Study Region ................................................... 115 Population Density ........................................................................................... 115 Patterns of Distribution of Non-whites ............................................................ 120 Socioeconomic Characteristics and Homeownership ...................................... 126 Local Roads Spending and Local Roads Stock ............................................... 128 The Local Road Revenue, State-Allocated ............................................. 128 Patterns of MTF Allocation in the Detroit Metropolitan Area ............... 129 The Locally-raised Road Revenue, Local Contributions ........................ 130 Analytical Results .................................................................................................. 140 Model Estimation ............................................................................................. 140 Patterns of Decentralization: Total Population ....................................... 143 Ordinary Least Squares Regression Results, Full Specification ....... 143 Spatial Regression Results, Full Specification ................................. 145 Ordinary Least Squares Regression Results, Reduced Form ............ 149 Spatial Regression Results, Reduced Form ...................................... 150 Summary of Findings: Decentralization of Total Population ................. 153 ix Patterns of Decentralization, Non-white Population .............................. 153 Relative Concentration: Ordinary Least Squares and Spatial Regression Results, Full Specification ............................................. 154 Relative Concentration: Ordinary Least Squares and Spatial Regression Results, Reduced Form .................................................. 157 Non-white Population Density: Ordinary Least Squares and Spatial Regression Results, Full Specification ................................. 159 Non-white Population Density: Ordinary Least Squares and Spatial Regression Results, Reduced Form ...................................... 161 Summary of Findings: Patterns of Non-White Decentralization ............ 164 Discussion .............................................................................................................. 165 Effects of Local Roads Spending ..................................................................... 165 Effects of Socioeconomic Factors ................................................................... 166 Effects of Racial Composition ......................................................................... 167 Effects of Spatial or Locational Attributes ...................................................... 171 CHAPTER SEVEN: CONCLUSIONS .......................................................................... 174 Summary of Key Findings ..................................................................................... 175 Conclusions and Implications ................................................................................ 177 Conclusions ...................................................................................................... 1 83 Contributions .................................................................................................... l 87 Theoritical Contributions ........................................................................ 187 Methodological Contributions ................................................................ 190 Policy and Broader Impacts .................................................................... 190 Limitations and Future Work ................................................................................. 192 Framework ....................................................................................................... 192 Data and Methods ............................................................................................ 195 APPENDICES ................................................................................................................ 200 Appendix A. List of Study Communities (cities and villages) in the Detroit Metropolitan Area .................................................................................................. 201 Appendix B. Dependent and Independent Variables: Untransforrned ......... j .......... 203 Appendix C. Bivariate Correlations ....................................................................... 205 REFERENCES ............................................................................................................... 207 Table 5.1. Table 5.2. Table 6.1. Table 6.2. Table 6.3. Table 6.4. Table 6.5. Table 6.6. Table 6.7. Table 7.1. LIST OF TABLES Changes in the Michigan Transportation Fund Distribution Formula ............. 98 Variables and their Sources ........................................................................... 107 Descriptive Characteristics of the Study Community .................................... 138 Coefficients of Standard and Spatial Regression (Full Model) Percent Change in Population Density: Detroit MSA, 1980-1990 ................ 148 Coefficients of Standard and Spatial Regression (Reduced Model), Percent Change in Population Density: Detroit MSA, 1980-1990 ................ 152 Coefficients of Standard and Spatial Regression (Full Model) Percent Change in Non-white Concentration, Detroit MSA, 1980-1990 ...... 156 Coefficients of the Standard and Spatial Regression (Reduced Model), Percent Change in Non-white Concentration, Detroit MSA, 1980-1990 ...... 158 Coefficients of the Standard and Spatial Regression (Full Model), Percent Change in Non-white Population Density Detroit MSA, 1980-1990 ...................................................................................................... 160 Coefficients of the Standard and Spatial Regression (Reduced Model), Percent Change in Non-white Population Density Detroit MSA, 1980-1990 ............................................................................... 163 Comparison of Significant Explanations of Decentralization Between the Total and Non-white Population ............................................... 177 xi LIST OF FIGURES (Images in this dissertation are presented in color) Figure 2.1. Percent of Population Living in Central Cities and Suburbs in US. Metropolitan Areas, 1910-2000 ....................................................................... 22 Figure 3.1. A Conceptualized Relationship between Local Roads and Population Decentralization ............................................................................ 64 Figure 5.1. The Study Area ................................................................................................ 80 Figure 5.2. Detroit Metropolitan Area Population Trend, 1900-2008 ............................... 83 Figure 6.1. Percent Population Density Change, Detroit MSA 1980-1990 ..................................................................................................... 117 Figure 6.2. Population Change by Travel Time: 1972-2002 .......................................... 119 Figure 6.3. Relative Concentration of Non-whites, Detroit MSA, 1980 ........................ 122 Figure 6.4. Relative Concentration of Non-whites, Detroit MSA, 1990 ........................ 123 Figure 6.5. Percent Change in Relative Concentration of Non-whites, Detroit MSA, 1980-1990 .............................................................................. 125 Figure 6.6. Household Median Income by distance from Detroit CBD, 1980 ................ 127 Figure 6.7. MTF Allocation: Proportion of the City of Detroit to the Total Metropolitan Region, 1952-2002 ......................................................... 131 Figure 6.8. Per Person State-allocated Local Road Revenue ($), Detroit MSA, 1977....132 Figure 6.9. Per Person State-allocated Local Road Revenue ($), Detroit MSA, 1987....133 Figure 6.10. Per Person Locally-raised Road Revenue ($), Detroit MSA, 1977 ............. 134 Figure 6.11. Per Person Locally-raised Road Revenue ($), Detroit MSA, 1987 ............. 135 Figure 6.12. Local Road Density, Detroit MSA, 1977 .................................................... 136 Figure 6.13. Local Road Density, Detroit MSA, 1987 .................................................... 137 Figul‘e 6.14. Percent Change in Population Density Model Residuals ........................... 144 xii CHAPTER ONE: INTRODUCTION Background to the Study Metropolitan areas, which are defined as “geographic areas with large population nucleus, together with adjacent communities that exhibit a high degree of social and economic integration with that nucleus” (U. S. Bureau of the Census, 2000), are dynamic human-dominated landscapes and their transformation remain an enduring subject in settlement formation, urbanization, and decentralization processes. In the US, the transformation of metropolitan areas has been characterized by profound shifts in demographic trends and distinct changes in the spatial distribution of people. These shifts have proceeded in two distinct spatial patterns. During the first half of the twentieth century, U. S. metropolitan areas developed into highly centralized regions primarily due to the industrialization boom. Ci ti es in the North and Midwest regions, in particular, became the dominant destination pl aces for people from international and domestic non-metropolitan origins, as well as for many Southern blacks who were attracted to better life and economic opportunities that the North could offer, and away from realities of racial persecution endemic in the South (Teaford, 1993). As a result, major cities such as New York, Chicago, and Detroit experi enced unprecedented population growth. By the 19508, many of these cities experienced their highest centralization point, thus the transformation of these cities into social, cultural, political, and economic pO‘Nel‘houses. Over time, however, the dominance of central cities in these regions waned althollgh cities like Chicago and New York have experienced some revitalization while cities like Detroit remained fiscally, socially, and ecologically challenged and immensely distressed. In the second half of the twentieth century, the explosive growth in suburban areas and/or the simultaneous and persistent out-migration of central city residents for suburban locations ushered a drastic transformation of metropolitan areas particularly in the North and Midwestern regions (Hobbs & Stoops, 2002). Hobbs and Stoops (2002) indicate drastic shifts in population distribution when they found that in 1950, the average population density in a given central city was 7,517 persons per square mile. Half a century later, in 2000, a central city had an average population density of 2,716 persons per square mile (Hobbs & Stoops, 2002; p. 38). In contrast, communities outside of central cities during the same time period experienced population gains, indicating an average population density increase from 175 to 208 persons per square mile. This pattern of reversal in population growth in central cities and suburban areas has been a well observed phenomenon in many Northeast and Midwestern cities in metropolitan areas in the US. The reversal in population trends has become increasingly understood in such terms as “decentralization” (Mieszkowski & Smith, 1991; Glaeser & Khan, 2001), “suburbanization” (Mieszkowski & Mills, 1993; Jordan et al., 1998), “counter urbanization” (Berry, 1980), dispersion (Boume, 1989), and the more general and catch- all phrase that many urban scholars label as “urban sprawl” (Squires, 2002; Duany et al., 2000; Breugrnann, 2005; Lopez & Hynes, 2003). This dissertation research uses the term decentralization to describe the geography of urban transformation characterized by significant population growth in suburban areas, while the central city experiences stagnation, slow growth, and in many instances, a substantial decline in population and economic activities (Hobbs & Stoops, 2002; Berube & Fonnan, 2002). Within metropolitan areas, decentralization has attracted much attention because of the fundamental change in the way people live, work, and play. Decentralization has prompted a widespread concern among urban scholars, interest groups, policymakers and their constituents and has stimulated extensive research on causation. At the metropolitan level, decentralization presents two primary problems that are inherently geographical. On one hand, decentralization results in central city decline and negative social and economic consequences. This means that for central cities, the decentralization of people is associated with capital and job flight, and fiscal challenges due to a diminished competitiveness of cities for attracting and retaining residents and businesses. Over time, the decline in central cities and its effects are disproportionately spread across different population groups, with African Americans and other ethnic minorities experiencing the brunt of poor public service provision, congestion, isolation, and a limited accessibility to jobs and other opportunities (Glaeser et al., 2004; J argowsky, 2002). On the other hand, decentralization affects suburban communities particularly since it imposes ecological challenges associated with the unplanned pattern of development in outlying areas (Squires, 2002; Power, 2001; Downs, 1999). Accordingly, beyond the central city, decentralization manifests in the following problems: 1) a significant loss of farmland and open space due to land development in support of housing and infrastructure needs (Lopez et al., 1988); 2) landscape fTi’lgl'nentation due to uncoordinated land use planning (Wilson et al., 2003), and; 3) environmental pollution due to excessive intrametropolitan driving (Handy, 2006; Johnson, 2001 ), among other negative consequences. Hence, residents in fiinge and outlying communities are also adversely affected but in forms and intensities that are different from central city residents. As the current pattern of decentralization threatens the fiscal, social, economic, and physical health of communities, the urgency to re-evaluate and recast public policies has intensified as has the quest for explanations that underlie it. There is widespread recognition that until the underlying factors of decentralization are well understood, policy responses will remain off target, if not significantly ineffective for reversing the decentralization of people, the sprawling pattern of grth in metropolitan areas, and negative consequences that are associated with these processes. This study will contribute to the understanding of some of the causes of decentralization that are currently not well understood. Specifically, the study will add to an understanding of the effects of government policy on the geography of opportunities for quality of life in general, and patterns of decentralization of people in particular. Furthermore, the study will examine the influence of local roads spending on the pattern of decentralization in metropolitan areas. An Overview of Causes of Decentralization in U. S. Metropolitan Areas Previous geographic research provides an understanding of decentralization of p€0ple in metropolitan areas as a process shaped by different factors and circumstances Operating at different geographic scales over time. These factors are inextricably linked I and are not easily disentangled. At the macro-scale, the out-migration of people and jobs from central cities reflect: 1) demographic transition including decreasing mortality followed by decreasing birth rates; 2) advances in communication and technology; 3) deindustrialization manifested in shifts from manufacturing to service based industry; 4) government policies on housing and highway development; 5) the convergence of military and aviation research along with advances in the air conditioning and refrigeration technologies in the South and West that further stimulated the reversal of migration flow from the “frostbelt” to “sunbelt” regions; and 6) the emergence of global cities that facilitated increasing diversity in cities and exchange of goods and services while these cities maintain command and global control over financial markets (Sassen, 2002; Bruegmann, 2005; Duany et al., 2000; Ebner, 1985; Fisher & Mitchelson, 1981; Berry, 1980; Squires, 2002). These macro 1eve1 causes reinforced metropolitan and local circumstances prompting changes in the spatial distribution of people and the overall metropolitan landscape. At the metropolitan scale, causes of decentralization range from individual wealth or financial status and other socio-economic factors that allow increasing mobility for some people (Clark, 2007, 2009; Freeman, 2008; Clark & Ware, 1997; Mieszkowski & Mills, 1993), to the variation of local community amenities that entice people to relocate in such communities (Bayoh et al., 2006; Koles & Muench, 2002; Clark et al., 2002), to race relations (Alba & Logan, 1993; Charles, 2003; Darden etal., 1987; Fischer, 2008; Iceland & Wilkes, 2006; J argowsky, 2002; Massey & Denton, 1993; Zubrinsky & Bobo, 1996), to changing taste and preferences for rural lifestyle (Belden et al., 1998), and to fCl’atures of the natural and physical environment that either restrict or accommodate exPansive development patterns (Burchfield et al., 2005). Another body of knowledge holds that the reality of local political fragmentation reinforced by uncoordinated local land use and growth control mechanisms has a significant contribution in shaping the decentralization in metropolitan areas (Byun et al., 2005; Ulfarsson & Carruthers, 2006). Overall, these mutually reinforcing metropolitan level and broader processes have significant effects in the way business, residential location choices, and recreation are realized. The Research Context and Questions While evidence suggests that the decentralization of people in US. metropolitan areas has been occurring since the first quarter of the century but proceeded more rapidly after the Second World War (Otterstrom, 2003; Hobbs & Stoops, 2002; Mieszkowski & Mills, 1993; Ebner, 1985), the pattern of decentralization of people by race has been distinctively uneven across groups. Minorities, defined as “all people who are Hispanic, and are races other than white including those who indicated White alone in Census 2000” (US. Bureau of the Census, 2000), have less participation in the decentralization process and the precise causes are far from settled (Clark, 2009, 2007; Fischer, 2008; Logan, 2003; Darden, 1990). In the last few decades, however, significant increases in suburbanization rates for blacks or African Americans and corresponding decreases in levels of their segregation from the majority whites have been observed in many metropolitan areas (Clark 2009; Fischer, 2008; Freeman, 2008). While it appears that there is an improvement or progress in the quest for residential integration particularly for blacks in many metropolitan areas in the country, interpretation of this trend must be pursued with caution. A closer scrutiny of the trend suggests that the increasing suburbanization of Afiican Americans does not readily equate to spatial assimilation and residential integration with majority whites. Blacks continue to experience the highest level of segregation from whites relative to their Asian, Hispanic, and other ethnic group counterparts (Alba & Logan, 1993; Chung & Brown, 2007; Fischer, 2008; Johnston et al., 2007). Essentially, there has been a sustained separation between the minority population groups from whites, and some cities like Chicago, Cleveland, Detroit, Milwaukee, Newark, and Philadelphia remain “hypersegregated”, which is a condition that characterizes higher levels of spatial separation of blacks from whites based on all five dimensions of segregation that include unevenness, isolation, clustering, concentration, and centralization (Massey & Denton, 1993; Wilkes & Iceland, 2004). This incidence of “hypersegregation” reflects a group’s lack of propensity and capability for social mobility and spatial mobility, which may explain the differential level of suburbanization across racial groups (Massey & Denton, 1993). The different patterns of decentralization and the sociospatial separation by race are significant social issues that continue to stimulate discussions among policymakers and urban scholars from many disciplines. These discussions reflect deep concerns for the sustained differential locational outcomes by race in metropolitan areas. Where there is a high disparity of levels of suburbanization and “hypersegregation” between racial groups, the segregated group is more likely to experience isolation (Wilson, 1987; Massey & Denton, 1993), a decline in access to employment and other opportunities (Darden et al., 1987), concentrated poverty (Wilson, 1987), higher incidence of teenage Pregnancy (Hogan & Kitagawa, 1985), poor school performance (Charles et al., 2004) and poor maternal and infant health outcomes (Grady, 2006). Because of these negative consequences, there has been an enduring interest in identifying causes of decentralization. More specifically, there has been an enduring interest on the causes of differential rate of suburbanization of non-whites and their locational outcomes. From a social geographer’s point of view, the differential rate of decentralization across racial groups have been viewed on the basis of the following perspectives: 1) ecological or spatial assimilation; 2) neighborhood preference; and 3) place stratification. These perspectives provide relevant theoretical foundations for much of the analyses regarding differential patterns of suburbanization and locational outcomes of minorities. According to the ecological perspective, the differential rate of decentralization and locational outcome is a result of competition, invasion, succession, and adaptation processes (Park et al., 1925; Alba & Logan, 1993; Darden, 1985, 2000; Lawrence, 2003). In empirical tests, the ecological perspective identifies socio-economic status measured in income, education, and occupation as primary determinants of patterns of decentralization by race. Further, results of these tests have shown that income, education, and occupation are significant explanations for the likelihood that an . individual or a group will assimilate with the majority population group, the whites, as the spatial assimilation theory asserts (Park et al., 1925; Massey & Denton, 1985). Therefore, individuals and population groups with better socio-economic characteristics are in a better position for relocating in suburban communities, which are places with better residential and locational endowments (Clark, 2009; Clark & Ware, 1997). Alternatively, the neighborhood preference perspective proposes that the differential rate of decentralization by race is an outcome of sheer individual choice for certain demographic composition and amenities in the “destination community” (Clark, 2009; Bouma-Doff, 2007; Freeman, 2000; Farley et al., 1997). The neighborhood preference perspective ties in with the place stratification perspective, which asserts that causes of differential decentralization by race are due to structural forces that induce the relocation of certain population groups in suburban communities while others, mostly minorities or people of color, are left behind in central cities. The main idea for the place stratification reasoning is that prejudice and discrimination cause people to distance themselves from certain population groups, particularly blacks or Afiican Americans and other ethnic minorities through the process of “white flight” and other discriminatory behavior (Gotham, 2002; Crowder, 2000; Alba & Logan, 1993; Charles, 2003). These three theoretical perspectives have been used extensively to analyze residential patterns and decentralization processes. However, prior applications and empirical studies of these tend to overlook impacts of public policies on patterns of decentralization. Specifically, the effects of policy on transportation development at the local level have had inadequate attention. It is possible that the lack of focus of policy impacts regarding local transportation may have obscured effects of the pattern of distribution of funds for the development of local infrastructures and amenities that serve local needs. Essentially, what is not captured in previous studies using one of these three perspectives is the potential effect of patterns of distribution of public funds across metropolitan landscapes and how these may have exacerbated differential levels of decentralization across population groups. To address the gap, a human ecology methodological framework is adopted in this dissertation research to understand the relationship between local roads and patterns of decentralization. The human ecology framework enables analyzing the relationship between roads and decentralization within a broad and holistic theoretical base. Specifically, this dissertation research focuses on local or non-highway roads and their possible influence in the decentralization of people by race. The Detroit Metropolitan Area in Michigan is the case study area. The research addresses three questions: 1) Do local roads matter in the decentralization of people? 2) Does the pattern of distribution of local roads investment facilitate decentralization? and 3) Does the pattern of distribution of local roads spending explain patterns of decentralization of non-whites in metropolitan areas? This research attempts to understand the relationship between local roads and patterns of decentralization, and the possible contribution of govermnent policy to this relationship. Roads, Government Spending, and Decentralization Roads and road building had become vital components in the evolution and transformation of human settlements even before the introduction of a formal road system and management strategies by the Roman empire in the pre-modern civilization (Bund, 1920). This transfonnative capacity of roads in a landscape is tied to the fact that roads are basic infrastructure for small villages and large and complex conurbations alike. Roads provide economic, social, and military or security benefits, and shape the internal structure of a place or a region. In the twentieth century, roads and road building in the United States have be- COme of paramount significance beyond these basic benefits. Roads and road building have been linked to the marked transformation of the social and physical landscapes 10 across the country. For instance, the social transformation in the U. S. particularly the birth of the civil rights movement has been linked to the events on the road and Rosa Parks (Hanson and Giuliano, 2004; p.3). In the same vein, roads and road building facilitated the spatial transformation of the metropolitan landscape, which manifests in the way people and jobs are distributed. Conversely, people have engaged in the process of landscape transformation through road building, which shapes the internal structure of any given place or region. A significant part of many discussions about the metropolitan landscape transformation has focused on the effects of government policies on roads and road building. This is not surprising given the fact that government policies are often invoked as major causes of decentralization in US. metropolitan areas (Hartgen, 2003; Voss & Chi, 2006; Baum-Snow, 2007). Indeed, research in the last few decades indicates the significance of the interstate highway development in the uneven growth across metropolitan areas, making some communities more attractive for residential and industrial relocation than others (Handy, 2005; Downs, 1999; Garrison et al., 1959; Rii, 1983). Thus, the significant impact of roads and road building on decentralization, and the policies that underlie these cannot be ignored. Roads and road-building have been subjects of intense discussions since these are linked to many positive as well as negative social, economic, and ecological outcomes. First, roads form a blueprint for local and regional transportation system, the network of waterlines, and other linear infrastructures. The capacity of these basic infrastructures determines how much growth can be accommodated in a given time peri Od. Second, roads enable local housing development, and social and economic ll activities to function. The quality of road services and related infrastructure can either serve as “pull” or “push” factors for residential relocation, which in turn affects local growth and land use change. Third, roads and highways enable infra—regional exchange with broader markets. The quality of roads services affects the nature of inter- metropolitan and intra-metropolitan mobility and accessibility in a given locale or region, which in turn affects industry location decisions that can trigger shifts in the distribution of people and jobs, and land use change (Hanson & Giuliano, 2004; Rodrigue, 2006). Thus, roads and road building are linked to the physical transformation and decentralization in metropolitan areas. These have also contributed to social transformation as the Rosa Parks experience has demonstrated. Essentially, roads and road building do not just have a paramount influence over the form and character of human settlements, but they shape the social landscape as well (Hanson & Giuliano, 2004; de Boer, 1986). Roads are intricately woven into the social fabric of community life. Their production and management entail complex processes, decisions, and policies. Ofientimes, these processes, decisions, and policies have unintended consequences that may provide benefits to some individuals and population groups but costs and injustice to others. High way Development and Decentralization As research shows, strong evidence for the hi ghway-decentralization connection exists. The highway development is recognized as one of the major facilitators of decentralization in metropolitan areas (Hartgen, 2003; Voss & Chi, 2006; Baum-Snow, 2007). Highways facilitated increases in spatial interactions between regions, linked 12 settlements across the country (Berry & Garrison, 1958; Berry & Horton, 1970), and the dispersion of economic (retail) activities (Brueckner, 2005). Additionally, highways generated spillover effects inducing the displacement of industries in one location and shifting them to another (Chandra & Thompson, 2000). For the most part, these displacements meant the deconcentration of jobs and people in central cities (Handy, 2005; Downs, 1999; Davis, 1996; Garrison et al., 1959; Rii, 1983), subsequently transforming the form, structure, and function of cities. Despite the strength of the evidence supporting the highways-decentralization connection, there remains much to be understood about roads and the possible facilitating effect that these may have on population decentralization in metropolitan areas. Some have cast doubt on the role of highways on decentralization (Gramlich, 1994), the direction of the causality (Kain, 1970; Zhang, 2001), and the possibility that factors other than the highway development have contributed to the decentralization in metropolitan areas. The ambiguity of the hi ghways-decentralization relationship raises questions on whether highways have directly contributed to decentralization or whether these merely serve communities that would have otherwise developed due to factors other than highway development. Such ambiguity requires a more comprehensive analysis of decentralization that accounts for other factors with possible synergistic and complementary effects. This dissertation research will contribute to this debate. 13 Local Roads and Decentralization The influence of local roads or non-highway roads on the decentralization of people is plausible and deserves further investigation. This is particularly so since similar to the functions that highways provide, local roads are relevant in the socio-spatial structure and development of local communities. Local roads enable connectivity between major roads or highways and local suburban communities, provide base infrastructure, and serve as an amenity that affects quality of life (Black, 2003; Hanson & Giuliano, 2004). Local roads also affect health and is linked to obesity (Saelens et al., 2003), and sense of safety (Darcin & Darcin, 2006; Marans & Sheehan, 2003). As such, local roads and their development have been given greater consideration than the development or delivery of other public goods and services like local parks, libraries, and police protection, among others. It is more likely that communities may exist without parks, police protection and all other types of goods and amenities but may not equally do without local roads that provide the basic infrastructure. Thus, the economic and socio- spatial relevance of local roads present strong rationales for examining the effects of local roads on the decentralization of people in a metropolitan area. While some urban scholars provide insights into the relationship between local roads and decentralization, only few have undertaken studies on the direct link between them. And these studies do not examine the impacts of local roads on racial differences in decentralization. There is less information on how local roads may directly spur the uneven decentralization of people in general and by racial groups in particular. Studies of local roads with reference to decentralization have primarily focused on costs (Burchell et al., 2002; Carruthers & Ulfarsson, 2003; Holcombe & Williams, 14 2008; Ladd, 1998) and efficiency and equity consideration of road investments (Mikelbank & Jackson, 2000; Siggerud, 2004), travel behavior (Cervero & Kockelman, 1997; Cervero 2003), health and quality of life (Vojnovic et al., 2006; Saelens et al., 2003), sense of community and other neighborhood social engagements (Toit et al., 2007), and economic and job creation (Guild, 2000; Kemmerling & Stephan, 2002). These studies indirectly link local roads to decentralization and the dearth of existing studies that directly link them provides mixed findings. Furthermore, none of these studies examined the impact of local roads on the differential rate of suburbanization across population by race. For these reasons, there is a substantial room for improvement in the existing literature on the relationship between local roads and the decentralization of people in metropolitan areas. Purpose of the Study The purpose of this dissertation research is to determine the causal relationship between local roads spending and the decentralization process between 1980 and 1990, a decade of continued population decline in central cities particularly in the Northeast and Midwest regions in the US. (Hobbs & Stoops, 2002; Otterstrom, 2003; Berube & Forman, 2002) and is therefore, a relevant time frame for analyzing patterns of decentralization and its causes. This research specifically examines the effects of local road stock and road spending on decentralization and the differential rate of decentralization for minorities in the Detroit Metropolitan region. The research determines the relationship between local roads and patterns of decentralization with proposed environment, population, and behavioral explanatory factors defined within the 15 human ecology conceptual model of decentralization. Ultimately, the study seeks to contribute to the on-going discussion of how government policies, through local roads spending, contribute to the decentralization process in the Detroit Metropolitan region and how that decentralization shaped the spatial pattern of sprawl between 1980 and 1990. The findings from this research shed insights into the role that government policies play in sustaining the disparity and spatial inequities across metropolitan areas. Specifically, the dissertation: l) develops a theoretical model of human ecology that integrates population, behavior, and built-environment input variables into the analysis of the causal relationship between local roads and decentralization; 2) determines the Spatial pattern of the state’s spending on local road development at the community level; 3) characterizes the spatial pattern of population density change and concentration of non-whites within these communities; and 4) determines the causal link between local roads and decentralization, by relating local roads and road stock to population density change and concentration of non-whites as measures of decentralization using the Detroit Metropolitan region as the case study region. The Research Framework For this dissertation research, the human ecology framework enables an understanding of decentralization as an outcome of dynamic interactions and relationships among population characteristics, behavior, and environmental factors. The framework conceptually situates an analysis of decentralization within the context of dynamic relationships among factors such as socioeconomic characteristics of the population using income and education variables, behavior using preferences for 16 residential location based on demographic characteristics and racial discrimination variables, and features of the built environment such as roads stock, road spending, and locational factors such as distance from the central business district (CBD). The relationship between government spending on local roads and decentralization is understood in terms of effects of local road spending due to improvements in intra—metropolitan accessibility. The relationship between socioeconomic characteristics and decentralization is viewed as expression of people’s capacity for social mobility, which translates into spatial mobility. The relationship between behavior and decentralization is understood in terms of individual and collective preference for local communities with particular demographic characteristics. As relationships and interactions change among these factors, the built environment and land use pattern change, and subsequently, the spatial distribution of people across the metropolitan landscape. Within the context of the human ecology framework, and with the goal of making contributions to the body of knowledge in the decentralization process, the dissertation focuses on local roads and government spending. More specifically, it seeks to determine how variation of these is linked to the changes in population density and concentration of non-whites at the municipality level across the study region, while accounting for income, education, home ownership, demographic composition, and locational factors. These proposed explanatory factors reflect three theoretical perspectives of residential patterns including spatial assimilation, neighborhood preference, and place stratification perspectives that are integrated into the human ecology framework of 17 decentralization adopted in this dissertation research. In sum, the human ecology adopted in this dissertation research orients an analysis of decentralization that recognizes the complex, multi dimensional, and dynamic nature of the decentralization phenomenon. The human ecology offers an inclusive framework for studying the possible effects of government policies on local roads fiom multiple but complementary perspectives. Significance of the Study This dissertation research contributes to the theoretical, methodological, and policy discussions on the decentralization process in metropolitan areas. First, the study’s focus on local roads extends previous conceptualization of decentralization as one that is explained, to a large extent, by the accessibility benefits derived through the major highways development. It addresses questions about the role of government policy at the local level on the decentralization of people and the racial differences in pattern of decentralization. The goal of the research is to determine the effects of local roads which may shed insights into the sustained segregation of minorities from the white majority population group. Second, using the human ecology as a methodological approach allows an integrated analysis of the relationship between local roads and the decentralization of people following a broad theoretical base that integrates government policies with pOpulation, behavior and environmental input variables. Third, empirical results have policy implications for the role of the government and possible local spending oversight on decentralization and its negative consequences. Findings would provide a strong justi fication for an objective policy change regarding the distribution of local roads funds. 18 The rest of this dissertation is organized as follows. Chapter Two provides a review of prior studies of the decentralization phenomenon and factors and processes shaping it. It also presents the theoretical perspective adopted in this study. Chapter Three provides the conceptual framework followed by Chapter Four, which presents the empirical model of the relationship between local roads and the decentralization process. Chapter Five presents the data and methods. Chapter Six presents the results of the statistical analysis followed by discussion of results. Chapter Seven provides the summary and conclusions. 19 CHAPTER TWO: RELEVANT LITERATURE Recognizing that the population decentralization in metropolitan areas is linked to many positive and negative consequences, urban scholars and policymakers have increasingly sought for concrete explanations that facilitate such transformation. Research has been extensive and findings based on analyses of decentralization from different vantage points suggest that causes of decentralization reflect a plethora of social, economic, demographic, political, and ecological variables. The goal of this chapter is to provide some of the major theoretical and empirical findings on decentralization and analyzes possible links between local roads and decentralization in metropolitan areas. This chapter is organized into four sections. The first section provides a brief description of the shifts in population trend in US metropolitan areas during the twentieth century. The idea is to present these shifts in population trend to establish the relevance for studying decentralization and its causes. This section also articulates common terms and concepts that are used to characterize the pattern of metropolitan growth. The second section discusses theoretical explanations of decentralization informed by the residential mobility and segregation literatures. This is followed by a review of the empirical evidence of causes of decentralization. The third section presents plausible links between decentralization and local roads. The chapter ends with a summary of causes of decentralization and identifies themes and variables for which an empirical model of the relationship between decentralization and local roads can be developed and tested in the context of the Detroit Metropolitan Area. 20 Decentralization in US. Metropolitan Areas Throughout the twentieth century, U.S. metropolitan areas experienced a steady grth though this pattern of growth proceeded in two distinct spatial patterns. During the first half of the twentieth century, cities and suburban communities experienced population growth, with cities growing at an unprecedented rate and concentration of economic activities. In the second half of the twentieth century, a reversal of the pattern of growth occurred with suburban areas gaining rapid population growth while central cities were experiencing a simultaneous stagnation, slow growth, or a significant population decline in some regions particularly in the North and Midwest regions in the US. (Hobbs & Stoops, 2002; Kim, 2007). As Figure 2.1 shows, U.S. metropolitan areas experienced a steady population increase between 1910 and 2000 with central cities indicating their highest centralization point in the 19503. It shows that on average, 32.8 percent of the total metropolitan population lived in central cities in the 19503. By the 19903, many metropolitan areas in the US were decentralized with old industrial cities in the Northeast and Midwest regions experiencing a “hollowing out” particularly in neighborhoods closest to a central business district, while few cities experienced renaissance and revitalization of different proportions (Berube & Forman, 2002). At the turn of the twenty first century, 30.3 percent of the total metropolitan population lived in central cities while 50 percent lived in suburban areas. This translates into an aggregate population loss for central cities by 2.5 percent (Hobbs & Stoops, 2002), despite the revival of some major cities in the Northeast and Midwest regions. These trends and spatial distribution of people in metropolitan areas during the second half of the twentieth century stimulated extensive 21 research on underlying causes and consequences. These have also elicited a number of terms or descriptors for characterizing the pattern of growth. 100‘ . ” , iCJSuburb -° ICentralcity a .. =3 80 F__ __ T7 E —-w 8 T a N ‘9. i a E i i 3 — m 8 I- “II o o\° I 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 I Year Figure 2.1. Percent of Population Living in Central Cities and Suburbs in US. Metropolitan Areas, 1910-2000 Source: Hobbs and Stoops, 2002. Demographic Trends in the Twentieth Century, US. Bureau of the Census Special Report, CENR No. 4. Definition of Decentralization The transformation in US. metropolitan areas particularly during the second half of the twentieth century has been described in terms such as decentralization, suburbanization, dispersion, counter urbanization, deconcentration, and urban Sprawl. Though these terms may have been defined and adopted in different ways, they emphasize a pattern of diffusion of people, jobs, and other phenomena in an uneven and unprecedented way. Specifically, these terms characterize an uneven pattern of urban 22 development with a specific reference to population growth and development in suburban areas while the central city experiences stagnation, slow growth, and in most cases, decline. Hoyt (1941) conveys his description of the US. urban transformation using the term “decentralization.” He notes that decentralization proceeds in two reinforcing ways. The city breaks up into small towns, and industries and people increasingly relocate in the peripheries. Boume (1989), on the other hand, uses the term “dispersion” to characterize a decentralized form of urban development. Closely related to Hoyt’s and Bourne’s description, Berry (1980) uses the term “counter urbanization” to emphasize population deconcentration in urbanized areas and the rise of smaller, low-density, and homogeneous communities as determining characteristics of the pattern of urban development. Berry’s definition calls our attention to a depiction of urban development that not only discusses the population shifts and urban-suburban interactions but also decomposes the pattern of development that results from these interactions by concrete measures of spatial distribution and demographic composition. Alternatively, many urban scholars have used the term “suburbanization” to characterize a process of increasing relocation of people and economic activities from the core to the peripheries. In essence, suburbanization is a term that has been used interchangeably with decentralization, dispersion, deconcentration, and urban sprawl (Fisher & Mitchelson 1981; Mieszkowski and Mills 1993; Jordan et a1. 1998; Carlino, 2000). Over the last few decades, scholarly and popular articles have increasingly described the pattern of development in US. metropolitan areas using the term “urban 23 sprawl” (Bruegmann, 2005; Squires, 2002; Lopez & Hynes, 2003). Urban sprawl is a “catch all” phrase that characterizes the range of concepts given above. While many urban scholars and policymakers are in agreement of the many negative consequences associated with the urban sprawl phenomenon, a general consensus about its definition and measurement is far from settled. For example, Lopez & Hynes (2003) identify nine attributes that are often used to characterize sprawl. These include: 1) low density development; 2) separation of land uses; 3) leap-frog development; 4) strip retail development; 5) automobile-dependent development; 6) development at the periphery; 7) employment decentralization; 8) loss of peri-urban, rural agriculture, open space, and; 9) fragmented governmental responsibility and oversight. These authors, however, argue that a measure of urban sprawl based on population density captures the core feature of the phenomenon. They developed a sprawl measure based on the concentration and density dimensions of urban sprawl. Galster et a1. (2001) emphasize land use dynamics as a core underlying dimension of urban sprawl. They identify eight distinct dimensions of land use pattern and measure of urban sprawl including: 1) density; 2) continuity; 3) concentration; 4) clustering; 5) centrality; 6) nuclearity; 7) mixed uses, and 8) proximity. Similarly, Ewing et a1. (2003) measure urban sprawl based on four land use dynamics including: 1) density, 2) land use mix, 3) degree of centering, and 4) street accessibility. These different dimensions accentuate urban sprawl as an outcome of land use dynamic, and stress highlight urban sprawl as a land use issue. Given above, the different dimensions and measures clearly elucidate the complexity of the sprawl phenomenon and its underlying causes. As the review of Lopez 24 & Hynes show, urban sprawl is a pattern of development that reflects aspects beyond land use dynamics to include spatial interactions through shifts in the flow and diffusion of people and jobs between central city and suburban areas. Essentially, urban sprawl represents social, economic, spatial, and ecological dimensions of human and environment relations. For the purposes of this dissertation research, the term decentralization is used to describe the uneven pattern of development in metropolitan areas. Specifically, decentralization is conceived of as a process involving population gains for communities outside of a central city between two time periods. Furthermore, the research treats decentralization as a pattern of suburbanization of people by racial groups. Thus, patterns of decentralization of the general and non-white population in metropolitan areas are analyzed. To operationalize decentralization, three indicators are used. These include: 1) percent change in population density, 2) percent change in relative concentration of non- white population; and 3) percent change in non-white population density. Furthermore, the terms decentralization and suburbanization is interchangeably used for the rest of the dissertation. Theoretical Background Decentralization has characterized many metropolitan areas in the US. in the past several decades and is understood as a significant out-migration of people from central cities to outlying areas. One prominent subject is the differential participation of various population groups in the decentralization process. Research has established that there is a 25 sustained difference in levels of suburbanization between majority whites and non-whites (Fischer, 2003; Iceland et al., 2002). Over the past several decades, non-whites have experienced increasing levels of decentralization (Charles, 2003; Fischer, 2003). However, their increased pattern of suburbanization does not necessarily equate to spatial assimilation with the majority white population (Fischer, 2008; Iceland & Wilkes, 2004; Charles, 2003). Blacks, in particular, have been suburbanizing but they continue to experience high levels of segregation from whites, leading some scholars to assert that a “reghettoization” instead of integration has been taking place in suburban areas (Alba & Logan, 1993). Accordingly, many US cities and metropolitan areas experience high levels of segregation, or for a good number of cities, continue to be “hypersegregated” as is the case for Detroit, Chicago, Cleveland. Milwaukee, Newark, and Philadelphia (Massey & Denton. 1993; Wilkes & Iceland, 2004). The high level of segregation between blacks and whites is not unparalleled. Blacks are the most segregated individuals compared to others in different racial and ethnic groups. According to the US. Bureau of the Census report in 2000, 58 percent of the Asian population lived in suburbs in 2000, up by 5 percent from 53 percent in 1990; 49 percent of Latino population, up by 3 percent from 46 percent in 1990; 39 percent of Blacks or African-American population up by 5 percent from 34 percent in 1990. As can be observed, Blacks or Afiican-American suburbanites remain significantly lower in number compared to Asian and Latino groups despite a comparatively similar rate of suburbanization across these population groups. Compared to whites, which was 71 26 percent in 2000, black suburbanization rate trails to white suburbanization rate by a significant 32 percent points (Logan, 2003). What explains the differential levels of suburbanization across racial groups? What might government policies on local community development contribute to the differential suburbanization of people by race? The causes of decentralization in general and differential suburbanization by racial groups in particular, reflect complex processes that interact at different geographic scales across time. The existing literature in social geography indicates three major theoretical perspectives underlying the differential pattern of suburbanization by race, including: 1) the ecological or place assimilation; 2) neighborhood preference; and 3) place stratification. These perspectives influenced much of the theorization of racial differences in decentralization and the sustained segregation in metropolitan areas. These perspectives are described in the next section. The Spatial Assimilation Perspective The spatial assimilation perspective asserts that individuals and population groups demonstrate differential mobility patterns and propensity to assimilate with the majority population group based on socioeconomic and cultural competence (Massey & Denton, 1985; Massey, 1985). Central to the spatial assimilation perspective is the notion that individuals and population groups will attain a greater life’s chances once adapted and assimilated with the majority population group. With its ecological underpinnings from the Chicago School of Sociology (Park et al., 1925; Massey, 1985), spatial assimilation perspective emphasizes “natural” processes involving competition, invasion, and 27 succession resulting in a spatial distribution of people based on “ability to pay” and acculturation or adaptive characteristics (Burgess, 1928). These characteristics — measured in income, education, length of stay, and language proficiency - determine social mobility which in turn, facilitates spatial mobility (Park et al., 1925; Massey & Denton, 1985). The literature identifies three ways that spatial assimilation could proceed including: 1) structural assimilation; 2) cultural assimilation; and, 3) segmented assimilation. Structural assimilation reflects a pattern of assimilation between minorities and the majority population group based on socioeconomic factors. It asserts that income, education, and employment facilitate suburbanization and increase the propensity for residential integration. Cultural assimilation, on the other hand, emphasizes the role of cultural adjustment — language proficiency, length of stay — in the quest for assimilation of minority population groups, particularly foreign-bom minorities, to the majority whites (Massey & Denton, 1985). Factors that reflect these two assimilation tendencies shape the third one, segmented assimilation. Models that analyze segmented assimilation reflect socio economic and cultural/contextual factors and how these offer “divergent destinies” or assimilation paths (Zhou, 1997; Portes and Rombaut, 1996). Central to segmented assimilation is the notion that context, which encompasses physical, social, cultural characteristics of the host community that immigrants come in first contact, determine their assimilation path. The immigrant could become: 1) an upwardly mobile and integrated with the host 28 community; 2) trapped in a culture of poverty; and 3) adapted or assimilated with the host’s culture but retains ethnic cultural traits (Zhou, 1997). The importance of spatial mobility in spatial assimilation is such that spatial mobility increases non-whites’ prOpensity for participation in the opportunity structure such as access to jobs, quality housing and education, and other quality of life factors. As assimilation theorists contend, spatial mobility is an important step toward racial integration and assimilation with the broader society (Massey & Denton, 1985, 1993; Massey, 1985). Therefore, a better participation of non-whites in the pattern of decentralization would enhance greater opportunities for assimilation and integration between groups. Since the focus of this study is about population decentralization in metropolitan areas, with central city population groups that are traditionally exposed to factors constraining social and spatial mobility (i.e., blacks or African Americans and Hispanics), the study reviews empirical evidence for structural factors and less attention has been placed for reviewing empirical evidence for cultural and segmented assimilation factors of spatial mobility although all three assimilation tendencies could operate simultaneously at the same time. Socioeconomic Status and Population Decentralization Socioeconomic status affects people’s propensity to assimilate with the majority population group (i.e. whites of Caucasian descent). The consensus among proponents of the spatial assimilation perspective, more specifically structural assimilation, is that measures of socioeconomic status such as income, education, and employment are 29 predictors of an individual or group propensity for spatial mobility. A number of studies by William Clark and others underscore the relevance socioeconomic status in residential location patterns. Clark and his associates provide evidence for the relevance of socioeconomic factors in the segregation of different racial groups from whites. In a study that uses data from the Multi—City Study of Urban Inequality, Clark (2007, 2009) found that socioeconomic matters in preferences for residential location among whites, blacks, Asians, and Hispanics in four major cities — Los Angeles, Boston, Atlanta, and Detroit. He found that income and education are consistent in explaining propensity for these racial groups to live in diverse residential places. For blacks, increases in income and education indicate increases in their propensity to live with whites in majority white neighborhoods. However, there is still a strong indication that preference for same race residential location persists across these racial groups. In particular, whites still indicate resistance to living in neighborhoods with high percentage of black residents, while blacks still indicate a preference for no less than 50% black and 50% other race combination. As these findings show, socioeconomic factors —- income and education — are significant factors in explaining residential patterns in decentralization in metropolitan areas. To analyze the segregation of blacks from whites in Southern California, Clark and Ware (1997) use dissimilarity and relative exposure indices of segregation across census tracts in Los Angeles, Orange, Riverside, San Bemardino, and Ventura for five categories of income and seven categories of education. By comparing dissimilarity and exposure indices for blacks and whites within the same income and education categories, 30 they find that decreases in levels of segregation of blacks corresponded with increases in levels of socioeconomic status. They concluded that socioeconomic status does explain segregation. Iceland and Wilkes (2006) provide a strong support for the relevance of socioeconomic status in residential patterns. Their study evaluated the relevance of spatial assimilation and place stratification perspectives in patterns of segregation for African-Americans, Asians, and Hispanics groups from whites in all US metropolitan areas for the period 1990 and 2000. They used the dissimilarity index to measure segregation between each of these racial groups and whites. Consistent with previous findings, Iceland and Wilkes find that the spatial assimilation perspective is well supported among Hispanics and Asians only. Blacks were found to have the highest levels of segregation for all time periods relative to Hispanics and Asians. Their findings indicate that high levels of socioeconomic status (measured in mean scores of education, income, occupation, and poverty status) are associated with lower measures of segregation specifically for Hispanics and Asians population groups, but not for blacks. However, Iceland and Wilkes (2006) find that the change in the socioeconomic status among blacks — increases in the number of blacks that moved out of the "in poverty" and "less than high school education" groups — affects segregation patterns. This finding shows that as blacks move up in the socioeconomic structure, they are more likely to experience less isolation from the majority whites. Essentially, blacks with higher socioeconomic status have a higher probability for participating in the suburbanization process and being assimilated with whites. 31 Support for the assimilation perspective is further stressed by Freeman (2008) when he re-examined the relevance of socioeconomic status on locational outcome of blacks in US. metropolitan areas at the individual level for 1970 to 2000. He found that household income and education explained the propensity of blacks to assimilate with whites. Accordingly, more high income and educated blacks live with whites than poorer and less educated blacks. The strength of this finding, however, was the same for all time periods, which suggests that while socioeconomic status matters, the strength of this relationship did not improve. This finding raises questions about other possible causes that may have contributed to the significant but “static” role of socioeconomic status in the pattern of mobility and residential outcome of blacks in metropolitan areas. Despite a consistent support for the spatial assimilation perspective in levels of suburbanization and pattern of segregation across metropolitan areas, the lack of improvement (i.e. decreases) in segregation across time periods and the sustained high levels of segregation of blacks from whites for all time periods in past studies, challenge the notion of the differential levels of suburbanization and segregation as a pure “class- based” phenomenon. The fact that the level of segregation for blacks with respect to other racial groups is consistently high regardless of geography contributes to this ambiguity (Clark, 1992; 2009). Blacks from central cities are as highly segregated as their black suburbanite counterparts relative to other racial groups (Darden et al., 1987; Darden, 2000; Clark, 2009). For these reasons, the role of race in residential pattern and the decentralization of people by race cannot be ignored. There is simply an overwhelming evidence to suggest that race is a pervasive explanation in residential patterns in US metropolitan areas. 32 The Place Stratification Perspective The place stratification perspective asserts that social barriers impede spatial mobility for many minorities (Massey & Denton, 1993; Charles, 2003). Central to place stratification perspective is the notion that society is hierarchically organized with different population groups ranked in such a way that the more advantaged groups locate in places with better living arrangements while disadvantaged groups remain in undesirable places (Charles, 2003). The main argument for place stratification holds that some population groups are not integrated with majority whites because of factors other than socioeconomic status. Scholarly works indicate that racial prejudice and discrimination against the disadvantaged population groups, particularly minorities and people of color. Racial prejudice and discrimination have been proposed as mechanisms for constraining social mobility, which in turn impede spatial mobility. Social Barriers to Population Decentralization Previous research has shown that there are many factors that are simultaneously at work in determining and sustaining the differential levels of suburbanization and separation between population groups (Massey & Denton, 1993). Generally, research motivated by place stratification perspective views the separation between racial groups as an expression of individual’s or group’s aversion for other groups on the basis of race (Darden, 2004; Jackson, 1994; Harris, 1999, 2001). In residential spaces, the geographical separation between racial groups tends to reflect: 1) individual avoidance due to prejudice; and 2) discrimination in the housing market (Squires, 2003; Williams et 33 al., 2005; Massey, 2005). These have become the core mechanisms for sustaining the pervasive separation across racial groups in residential spaces (Charles 2003; Darden, 2003). The most recent finding that suggests a possible presence of factors that reflect the place stratification perspective in residential pattern comes from the work of Fischer (2008). Fischer finds that the average decrease in suburban segregation of blacks from all other racial groups — including whites, Hispanics, Asians and those categorized as “all others” — in 248 metropolitan areas across the US. corresponded with areas that experienced rapid increases in the black population. Fischer alludes to the notion that suburban residential landscapes are reconfiguring consistent with “white tolerance thresholds for contact with blacks, or other factors related to place stratification” (p. 492). Different tolerance levels for integation contribute to residential segregation and are a hindrance toward suburbanization for minorities and their residential integration with majority whites (Clark, 1992). In his study in Los Angeles, Clark found that individuals are more willing to move into neighborhoods with a race combination that is similar to their own. He found those who indicated “no preference” mostly moved into their own-race neighborhood. Whites prefer same race the strongest while blacks prefer the same race the weakest. Also, whites would prefer to move into neighborhoods with low percentage blacks, while blacks prefer to move into a 50 percent black and 50 percent other races (Charles, 2003; Farley, 1995). This behavior suggests that while there is some acceptance for the idea of an integrated neighborhood, there remains an overwhelming unwillingness for actually sharing residential spaces (Clark, 2009; Farley, 1995). This evidence shows differences in tolerance levels for people of different race 34 and culture. Such tolerance level may reflect motivations for establishing a well-defined racial line among different groups. Massey & Denton published the American Apartheid (Massey & Denton, 1993), one of the most important works that illustrates the effects of prejudice and discrimination in residential spaces. By studying the pattern of segregation across major cities in the US, these authors show an extreme isolation of blacks from education and employment opportunities combined with “white flight” perpetuates the “black underclass.” These authors indicate that prejudice and discrimination impede blacks from participation in the opportunity structure in suburban areas particularly in jobs, education, and housing market. A significant amount of support for place stratification factors in explaining different levels of suburbanization for minorities or people of color, particularly blacks, can also be gleaned from segregation studies that consistently found high levels of pattern of segregation between blacks and whites relative to other racial groups. Iceland and Wilkes (2006) demonstrate that scale and lack of within group variation make a difference in explaining high level of segregation between blacks and whites at the metropolitan level for the years 1990 and 2000. Contrary to Asian and Hispanic population groups, the residential pattern for blacks does not support the spatial assimilation reasoning. Blacks’ residential segregation does not improve (decrease) with increasing socioeconomic status at the metropolitan level. The authors regard this finding as a support to place stratification reasoning. However, a further analysis of within-black socioeconomic status and its effect on level of segregation yields an interesting result. The authors show that blacks with higher socioeconomic status tend to live in less 35 segregated areas than their poor black counterparts, implying that socioeconomic status still does matter in explaining the residential pattern but with exceptions. Johnston et al. (2007) revisits the work of Massey and Denton (1988) on segregation measures and applied the 5 dimensional segregation indices at the census tract level between whites and three racial groups, namely: blacks, Hispanics, and Asians. Consistent with prior findings, Johnston and his associates find the segregation of blacks the highest. Similarly, Logan et a1. (1996) find that socioeconomic factors — homeownership, income, education, and nativity/language — explain residential pattern for Hispanic and Asians but not for Blacks. Both studies Show that there is a greater exposure of Asians and Hispanics to whites in residential areas but lesser for blacks. Darden and his associates undertook a series of studies to test the relevance of ecological theory on suburbanization and segregation across different ethnic groups (Darden, 1977, 1985, 1986, Darden et al. 1987; Darden & Kamel, 2000). Their consistent finding shows that blacks lag in levels of suburbanization, and empirically shows that race essentially distorts the ecological theory. For example, Darden (1990) indicates that professional status enables whites, Asians, Hispanic, and American Indian in the North Central Region to experience higher suburbanization rates. This did not appear to be the case for blacks with professional status. Darden contends that participation in suburbanization across these population groups “exists along a continuum defined more by race than socioeconomic and professional status (p. 20). Suburbanization rates for these population groups based on professional status were found to proceed in the following order: whites, American Indian, Asians, Hispanics, and blacks. 36 Similar tests were undertaken by Darden in Kansas (1986) and Chicago (1987). He examined the residential segregation between blacks and whites, while controlling for socioeconomic status —— occupation, income, and education. The analysis of both yields a strong support for the significance of race in the segregation of blacks from whites. The black-non Hispanic white segregation was consistently high despite the Similarity in level of socioeconomic status between blacks and non-Hispanic whites communities that were studied. In Detroit, patterns of segregation between blacks and whites were high in central city but a much higher pattern was observed in the suburbs (Darden et al., 1987; p. 87). This finding leads many scholars to believe that the residential pattern in Detroit fits well with the process of “reghettoization,” a description for a process whereby “re— segregation” rather than dispersal of blacks in suburban areas is occurring (Clay, 1979). As these studies show, race has been shown to be a pervasive factor in the sustained separation across different racial groups. The different tolerance levels, individual prejudice, and a consistent finding of the high levels of segregation between Blacks and whites relative to other racial groups demonstrate the strength of the Place Stratification perspective for understanding the differential levels of suburbanization and pattern of segregation in metropolitan areas. Discrimination in Housing Empirical evidence also shows that segregation is an outcome of institutional forms of discrimination that are prevalent in the housing market. These discriminatory practices occur in the real estate, lending, and insurance industries. There is also a strong evidence for the influence of government agencies and programs at different levels, and 37 local jurisdictions. However, the manner by which these discriminatory practices are carried out are not easily detected, ranging from overt to covert practices that have become sophisticated and undetected over the years (Williams et al., 2005; Massey, 2005). Institutional forms of discrimination in the housing market have been carried out by real estate and financing industries through the practice of imposing restrictive covenants, red lining (Massey & Denton, 1993; Yinger, 1995), block busting (Sugrue, 1996), racial steering (Yinger, 1995), and by denying home mortgage loans even when applicants (mostly blacks) are qualified to receive approval for financing (Yinger, 1995; Alba and Logan, 1993). Excluding black realtors from participating in white dominated realtor’s organization was practiced (Darden, 1977, 2001), as well as discrimination in the property insurance industry (Squires, 2003). Blacks were also subjected to the “color tax”, a phenomenon that a resident pays for being black in America (Darden, 1973). Blacks were paying higher rent than whites for housing of the same quality or equal rents for lower-quality housing. The pervasiveness of discriminatory practices resulted in the uneven homeownership rates across racial groups in the US. (Haan, 2007). It led to many policies and programs that attempt to mitigate discrimination in the housing market. The impact of these policies, however, remains vague. According to Williams et al. (2005), “discrimination in the housing market has become increasingly difficult to detect and decreases in incidence of abuses may not reflect the reality.” Indeed, the Housing and Urban Development has reported that an estimated two million or more abuses in housing 38 discrimination in the US occur. These and many more incidents of abuses at different stages involved in buying or renting a home are unreported (Farley & Squires, 2005). Because housing discrimination has become increasingly undetected, Williams et al. (2005) suggest that percent homeownership would be a relevant measure for detecting discrimination in housing. The percent homeownership at a disaggregate level across different racial groups provide a sense of the distribution of mortgage lending activity. It is also a relevant indicator for successful mortgage lending that can possibly provide an indirect way for measuring discrimination in lieu of the “paired audit” approach, which is one of the more sophisticated and resource intensive form of uncovering discriminatory behavior in the housing market (De Rango, 2001; Galster, 1992). Overall, the place stratification perspective provides an alternative interpretation for sustained separation across racial groups. The differential levels of suburbanization reflect individual prejudice, and differential levels of tolerance facilitated by institutional forms of discrimination in the housing market. These have significant effects for how preference for certain neighborhoods is shaped. Indeed, research has shown that the neighborhood preference perspective ties in with place stratification and intersects with features of spatial assimilation perspective. Therefore, all three perspectives are mutually reinforcing theoretical explanations for the differential levels of suburbanization and pattern of segregation. 39 The Neighborhood Preference Perspective The neighborhood preference perspective asserts that residential segregation is a function of a group’s or individual’s preference for a particular residential location (Schelling 1971; Clark, 1991; Clark & Fossett, 2008). Central to this perspective is the notion that individuals and groups have a propensity to reside in communities with a demographic combination that they perceive desirable. It highlights the notion that residents locate in particular communities as a manifestation of “in-group” attraction among residents (Chung & Brown, 2007; p. 314). Hence, the spatial distribution of people by race can be understood as an individual choice or voluntary decision to reside in a particular placed based on the demographic composition of the destination community (Clark, 1991; Farley, et. al., 1979). Preference for Homogeneous versus Integrated Neighborhood Studies on preferences for residential neighborhood based on racial composition have provided a consistent finding for all racial groups. Generally, the finding shows that different racial and ethnic groups tend to exhibit an “own race” preference for residential location (Clark & Fossett, 2008; Clark, 2009). For example, findings from the Multi-City Study of Urban Inequality (MCSUI), which was a multi method survey to understand issues related to poverty and urban inequality, provides compelling evidence for the relevance of neighborhood preference perspective in patterns of decentralization. Analysis for Detroit, Boston, Atlanta, and Los Angeles reveal similar finding with regards to preference for neighborhood composition among blacks and whites. Blacks prefer an integrated neighborhood with a combination 40 of 50 percent blacks and 50 percent other race (Clark, 1991, 2009; Farley et al., 1997). Blacks’ preference for integrated neighborhood increases with decreasing education and income. Accordingly, nearly half of blacks with low income also preferred an integrated neighborhood. On the other hand, middle class blacks prefer neighborhoods with the greater presence of white residents (Clark, 1991, 2009; Farley et al., 1997). For whites, they tend to have a stronger preference for low percentage of blacks in their neighborhoods. The overall finding for all racial groups in the study reveals that whites, blacks, Asians, and Hispanics, all have a strong “own-race” preference in their choice of residential neighborhood. Except for whites, however, all racial groups indicated preference for integrated neighborhoods. The analysis of Farley et a1. (1997) with regards to the Asian racial group deserves further examination. Farley and his associates find that the tolerance of whites increases with Asians and other fair skinned minorities especially those of whites of Hispanic origin. This behavior has been described as one consistent with the concept of “desirability continuum,” in which members of white ethnic groups are viewed as less inferior than Orientals, and the latter were seen as more desirable than blacks (Lieberson, 1980). Results from studies on residential preferences reviewed above indicate individual preferences for certain demographic characteristics as underlying explanation for residential patterns. It is clear that preferences for residential spaces are influenced by factors other than an individual’s “ability to pay” status (Clark 1992, 2009). It appears that perceived hostility in the destination community is a relevant factor affecting an individual’s preference for certain residential locations. 41 The Role of Government Policy in Population Decentralization The review of the different theoretical perspectives and empirical evidence for racial differences in decentralization and segregation areas reveals two things. First, the existing literature of residential pattern and segregation are not clear about the direct effects of government policies on sustained pattern of separation in residential spaces. There is a lack of study that demonstrates a possible direct effect of local policies in the separation of people by race. And, a study that directly links government policies, particularly local roads spending policies on decentralization is not adequate. Second, theoretical perspectives that motivate studies about underlying processes of suburbanization and segregation are clearly not mutually exclusive (Chung & Brown, 2007). Most of the existing studies analyze residential pattern using one or two theoretical frameworks and neglect to recognize that understanding complex processes like decentralization and segregation require a multiple perspective approach. Thus, this study is an attempt to understand the effects of local roads on racial differences in decentralization. It does so by using a human ecological methodological framework, which accommodates an analysis of the relationship between roads and decentralization using a broad theoretical base and multiple perspective approach. Government Policy on Roads and Decentralization Roads and road building are basic infrastructures that shape human settlements. Indeed, roads serve as a blueprint to any land use organization and formation and facilitate spatial interactions (Black, 2003). Roads serve as a major conduit for growth in one location and decline in another (Boamet, 1998). The extent that roads, both highways 42 and local roads facilitate accessibility and reduce transportation cost, roads can be viewed as a significant facilitator of decentralization in metropolitan areas. Indeed, the pattern of decentralization in metropolitan areas has been tied to government policies on road development. Empirical evidence shows that roads, specifically highways, have facilitated the dispersion of people and jobs across metropolitan areas and regions throughout the country. Baum-Snow (2007) finds that a constructed highway that passes through a central city impacts the population distribution of the total metropolitan area. He estimates that a constructed highway in a metropolitan area that passes through a central city reduces that city’s population by about eighteen percent (18%). Additionally, his finding shows that the city would have grown by eight percent (8%) if the highway system was not constructed. In another study about highway impacts, V058 and Chi (2006) find that the expansion of all major highways in the state of Wisconsin increased the population of - surrounding communities. They estimate that between 1970 and 2000, metropolitan civil divisions (MCDS) that are located ten to twenty miles away from an expanded highway experienced population growth. A similar finding related to the decentralizing effect of interstate highways comes from Chandra and Thompson (2000), who find that retail activities across regions are redistributed due to the construction of a highway system. The constructed highway displaced some industries in one county and shifted them to another (Chandra and Thompson, 2000). The study of Haugwhout (1999) reinforces and sheds additional light to the link between infrastructure investment (including transportation) and pattern of employment distribution. Haughwout (1999) used a spatial equilibrium model to specify the marginal 43 effects of infrastructure investment and found that state infrastructure investments tend to facilitate spatial distribution of growth in favor of the suburban or less dense areas within the state. His findings indicate that infrastructure investment affects the relative attractiveness of places and redirects the spatial allocation of economic activities. He also stresses that central cities are underprovided when it comes to public investment and tend to cope with maintaining extensive infrastructure stock while the tax base or local fiscal support declines. A similar analysis of the impacts of infrastructure investment on economic development was undertaken by Berechman et a1. (2006). This study provides evidence for highway development impacts at different spatial and temporal scales. Berechman and others attempt to verify previous findings on the differential effects of transportation investment on economic development given spatial/ geographical and time lags. A production function type of the basic model was estimated, with output as the dependent variable, and labor, private capital, public capital (transportation capital) and unemployment as independent variables. A lagged model in which 1 to 5 years time lags were introduced was estimated to test for possible delays in output response to additional transportation investment. Another model tested for spillover effects on neighboring areas via the Moran’s 1 spatial autocorrelation test. The results from an analysis of data on 48 states across the U. S. for the periods 1990 and 2000 indicate a significant impact of transportation investment on production output at different geographical scales including state, county, and municipality. Results further indicate output elasticities of 0.37, 0.34, and 0.01 for state, county, and municipality levels, respectively. Finally, the “spillover” effects of highway investment were found to have mostly affected 44 municipalities. This means that impacts of highway investment onto neighboring areas where highways are located tend to increase at a decreasing level of analysis (i.e. from state to municipality). Clearly, these studies provide a strong evidence for the spillover and dispersive effects of interstate highways and have shown that highways promote benefits and advantages in some places, but costs and disadvantages in others. Also, these studies provide an evidence for the transformative capacity of highway development in urbanized areas from mono-centric to complex polycentric urban environments in just a few decades. Potential Links between Local Roads and Decentralization While highways and major throughways were found to facilitate the decentralization in metropolitan areas, the role of local roads particularly in non-whites’ participation in the decentralization process is not quite well understood. Two explanations are appropriate at this point. First, aside from the scant literature on the relationship between local roads and decentralization, findings about the relationship tend to be mixed. A second reason, which is tied to the first, is that most studies that address local roads do not focus on decentralization but other outcomes such as costs of investment on infrastructure and urban form, and local roads and travel or commuting behavior. These studies often neglect an analysis of local roads as if these do not matter in household relocation decision. Further, these studies do not shed any information about the possible facilitative and dispersive impacts of local roads investment. Essentially, without a direct analysis of the relationship between these processes, it is not clear 45 whether local roads or government spending on local roads, indeed, spurs decentralization. Hartgen (2003) finds a weak relationship between them roads and growth in North Carolina. He shows that only about 15 to 25 percent of the variation in grth is explained by road improvements such as urban and rural widening. He concludes that prior population density level, not road investment, appear to have more significance in explaining the pattern of growth in the twelve commuting regions that comprise one thousand five hundred fifty one or 1551 census tracts in North Carolina during the 19903. Vojnovic (2000) on the other hand, shows a positive association between municipal expenditure on roads and suburban sprawl in the Metropolitan Area of Toronto. Both studies, however, did not directly explain how the relationship is linked to non-whites’ pattern of decentralization. The discrepant findings from these studies may be related to place (i.e., Toronto versus North Carolina), scale of analysis, and time period covered in the study, and show the complexity of this research question. The paucity of studies and a lack of consistent results on the relationship between local roads and the decentralization of people in metropolitan areas necessitate further research. Most existing studies on local roads focus on costs, and urban form and travel, and overlook addressing the possible local roads-population decentralization relationship. For example, in determining the relationship between urban form and different types of government expenditures, Burchell et a1. (2002) examined the relative costs of infrastructure, land, services, and housing, and compared these costs within the context of sprawl (sprawl being characterized by low-density development) and compact or high density pattern of growth at the county level in different regions in the US. Specifically 46 for local roads, these authors find that between the projected years 2000 and 2025, a projected cost saving to the US government is 188,305 or 9.2 percent of lane miles and $110 Billion or 11.8 percent of road costs under the compact and high density urban form. Unfortunately, Holcombe and Williams (2008) do not support their finding. These authors examined population density as it relates with per capita municipal government expenditure including infrastructure, services, and total expenditure in 487 large and small cities across the US and show that higher population density does not lower per capita government expenditures. On the other hand, their test on the relationship between population density and infrastructure expenditures yields the expected result, indicating that higher population density lowers infrastructure cost in small cities. Unfortunately, only highways and sewer expenditures were included in their study and local roads were ignored in the measure of infrastructure. Despite the lack of emphasis on local roads in the study by Holcombe and Williams, other findings in their study show the benefits that could be gained from higher density development particularly for small cities. Residents in small cities with higher density are more likely to achieve economies of scale from infrastructure services, which translates into lower cost on infrastructure services for individual residents. The inconsistent findings about urban form and the cost of infrastructure development to the government resonate in other areas of study such as in commuting and travel behavior (Cervero & Kockelman, 1997; Cervero, 2003). Most studies within this domain test for the relevance of some planning design principles (i.e. neotraditional and smart growth) on travel behavior and further evaluate whether or not development 47 pattern that reflects any of these design principles are effective in reducing private motorized commuting and curbing the pattern of urban sprawl. Thus, local roads are implicitly considered in these studies but the direct link to population decentralization is not analyzed. For example, Cervero and Kockelman (1997) find that impacts of urban form based on different physical design elements (density, diversity, pedestrian-oriented design) alter travel behavior in terms of a reduction in non-work trips, and increases in non- motorized travel. The study finds that neighborhoods with gridiron street designs and restricted commercial parking are significant variables in reducing household level non-work related vehicle miles traveled (VMT) and the use of single occupant vehicles. However, their finding is contradictory to what Crane and Crepeau (1998) found in their study on the relationship between street design and travel behavior. The latter find no significant link between street network pattern and short and long-term non-work travel behavior. In another study, Sultana and Weber (2007) find that travelers from communities characterized by pattern of urban sprawl (i.e. low-density) tend to experience longer commute time and mileage. Their findings also show that socioeconomic characteristics of the travelers are equally important factors in commuting behavior. The finding implies that in explaining commuting behavior, socioeconomic characteristics and the pattern of development that the commuters reside are closely interwoven and either attribute or factor could explain commuting behavior alone. As these studies show, there is a lack of an analysis of the direct relationship between local roads and decentralization. The existing studies reviewed do not examine 48 whether a particular urban form (i.e. low-density, high-density, and pedestrian-oriented) given its corresponding type of road network (i.e. gridiron) is given consideration in individual or household relocation decisions. Moreover, these studies do not provide insights into possible mechanisms by which local roads or the type of road network in a given community facilitates the decentralization of people by race. So far, existing studies on local roads and decentralization or sprawl, presented above are informative but findings are still inconclusive. The paucity of studies that directly assess local roads impacts on decentralization contributes to such gap. This study attempts to contribute in filling this gap. Summary This chapter provides a brief description of the shifts in population trend in US. metropolitan areas during the twentieth century. It emphasizes the post World War 11 population decentralization and assesses existing literatures related to its underlying causes. A review of the relevant theoretical and empirical evidence reveals the lack of information on the direct relationship between local roads spending and decentralization. However, informed by three theoretical perspectives in patterns of residential mobility and segregation, the review highlights education, income, demographic composition that defines the homogeneity or heterogeneity of communities, incidence of housing discrimination, and locational or spatial attributes as determinants of patterns of decentralization. The next chapter discusses a conceptual framework that reflects a multi perspective approach in understanding the decentralization of people in metropolitan areas. Using a human ecology methodological framework, the role of government policy 49 is integrated into a broad based human ecology conceptual model that recognizes explanatory factors shaping decentralization from spatial assimilation, place stratification, and neighborhood preference perspectives. These theoretical perspectives were used to identify the proposed explanatory factors of patterns of decentralization across the white and non-white population groups. 50 CHAPTER THREE: THE CONCEPTUAL MODEL This chapter builds upon the review of the relevant information related to the decentralization and residential patterns in metropolitan areas presented in Chapter Two. It draws from the different theoretical perspectives of decentralization and segregation — spatial assimilation, place stratification, neighborhood preference perspectives — as theoretical foundations for the development of a conceptual model of the relationship between local roads and decentralization of people in metropolitan areas. What follows describes a human ecology conceptual model that characterizes the causal relationship between local roads and decentralization. Using human ecology, the conceptual model developed for this study situates the role of government policy within other proposed explanatory factors based on the review of the three existing interrelated theoretical perspectives of decentralization and segregation. This conceptual model reflects a broad and holistic theoretical base that recognizes the essence of population, behavior, and environment factors shaping pattems of mobility and spatial distribution of people across space. Further, the model helps orient an analysis of patterns of decentralization that is inclusive and recognizes the complex, multidimensional, and dynamic features of the decentralization phenomenon. The chapter begins with an overview of human ecology followed by the description of the conceptual relationship between local roads and the decentralization of people in metropolitan areas. The last section lists the hypotheses of the study. 51 The Human Ecology Framework The subject of human ecology is recognized to have existed long before the concept was formally institutionalized in the 19203 (Borden, 2008). It is a subject with a rich intellectual tradition beginning when the term “ecology” was introduced by Haeckel in 1866 (Lawrence, 2003) and has become a foundational concept for many ecological studies of human systems particularly in the social science disciplines. Gross (2004) alerts us to the fact that human ecology was conceptualized and applied in different ways as different disciplines (i.e. geographers, sociologists, and ecologists) discovered or rediscovered the relevance of the human ecology framework in analyzing population/human and environment relations. This means that human ecology has been defined and conceived of in different ways, mostly reflecting disciplinary orientation and perspective (Borden, 2008; Gross, 2004; Lawrence 2003). It has been defined and conceived of as an approach, framework, method, study, program and has a wide range of application across the social and natural sciences (Gross, 2004). This dissertation research uses the conceptualization of human ecology as understood by sociologists and human geographers particularly among social geographers, which primarily conceptualizes human ecology as a study of human environment relations treats human ecology as an approach for analyzing human systems that recognizes complex, multi dimensional, and dynamic nature of such systems. As the subsequent paragraphs would show, human ecology as a framework has had a strong presence in both sociology and geography disciplines. The subject of human ecology has stimulated extensive discussions with scholars from both disciplines forging areas of 52 agreements and disagreements as they attempt to erect disciplinary boundary and identify “catchment areas” (Gross, 2004). Sociological Interpretations of Human Ecology The sociological literature traces the origin of human ecology to the works of Park, Burgess, McKenzie and others at the Chicago School of Sociology during the first half of the twentieth century. In its original interpretation, the sociological perspective of human ecology advanced by Park and others adopts biological concepts in plant and animal ecologies, and emphasizes processes of competition, invasion, and succession as core processes underlying human systems (Park et. al., 1925). Park defined human ecology as a “study of the spatial and temporal relations of human beings as affected by the selective, distributive, and accommodative forces of the environment” (Park, 1925; p. 63). This interpretation of human ecology essentially treats human ecology as a theory for studying human populations and their ability to adapt to the changing environmental conditions and the patterns of land use organization that result from the adaptation process. Essentially, human ecology emphasizes evolutionary processes underlying the formation and growth of cities--“from simple societies to complex conurbations” (McKenzie, 1967; p.73). The pioneering authors of human ecology were not only interested in describing the pattern of physical and social structure of the study area (i.e. the City of Chicago) and their changes but also the effects or consequences of these changes on social behavior and institutions. Further, these authors were keen about understanding how spatial relationships are linked to urban residents’ experiences with life in the cities including 53 psychological, moral, and spiritual aspects of their experiences. As such Park and his associates focused on the analysis of segregation, culture, vice, mental illness, divorce and family issues, and a host of sociological issues using neighborhoods in the City of Chicago as study areas. In articulating the human ecology framework, Park emphasizes a model of urban change characterized by four co-evolutionary interacting variables or components, which is similar to a human ecological model adopted by human geographers (Meade, 1977; Meade & Earickson, 2000). The components include: 1) population; 2) artifact (technological culture); 3) customs and beliefs (or the non-material culture); and natural resources (Park, 1936; p. 15). Park’s human ecological framework highlights the essence of the population-environment relations in shaping social and spatial structure of cities recognizing that technology (i.e. transportation technology) and non-material culture/behavior (social organization) are equally significant components aside fiom population and the enviromnent. The recognition of the technological culture in the human ecology framework is noteworthy. The advances in technology, particularly transportation technology has played a significant part in urban growth and the sociospatial transformation of cities and metropolitan areas, as the next section would reveal. The Classic Ecological Models Three major ecological models, which include the Burgess Concentric Zone, Hoyt’s Sectoral model, and Harris and Ullman Multiple-nuclei model are recognized as classical human ecological models for explaining change in sociospatial structure and 54 growth in cities. The Burgess Concentric Zone model (1925) presents a dynamic theory for the social and land use organization of the City of Chicago. In this dynamic model, competition, invasion, succession, and adaptation processes, which are core to the human ecological perspective of urban spatial change, are processes underlying residential and neighborhood change. The model, presents the notion of the “survival of the fittest” advanced in the study of animal and plant ecologies, wherein individuals and social groups are conceived of as competing for survival. In urban systems, population groups compete for the best and most desirable locations in a given locale, such as in a neighborhood, city or metropolitan region based on economic factors. Burgess theorizes that the outcome of competition is a land use organization shaped in concentric rings reflecting competitive advantage for certain activities and social groups with respect to a central business district (Burgess 1925). Burgess describes the city pattern as consisting of five zones: Zone 1 is the central business district (CBD) where intensification of land use is prominent and commercial, financial, administrative, recreational, and other institutional services are located; Zone 2 is the zone of transition, which is occupied by poor and old residential establishments, and where spillover of businesses and light manufacturing establishments are located; Zone 3 is the working class zone; Zone 4 is the upper class residential area; and, Zone 5 is the commuter zone or suburban area, which is mostly devoted to new developments. As described above, these different zones reflect a land use organization that describes the pattern of city growth through mechanisms of change involving competition, invasion, and succession processes described above. As a result of these 55 processes, activities of each zone tend to extend to the next, thus shaping neighborhood change and land use organization. The effect of competition and evolution on urban growth has been viewed by Hoyt (1939) from a different dimension. The sectoral model of Hoyt (1939) is an extension to the Burgess’s concentric zone model. It proposes that expansion of urban areas follow a sectoral and wedge-like pattern rather than concentric rings, and grants importance to transportation routes such as highways in the growth and expansion of cities. It incorporates both distance and direction from a central business district in the analysis of the pattern of urban expansion and growth, expressed in residential patterns based on class structure (Yeates, 1965) and in the present land use organization, commercial development along highway transport routes (Boamet, 1998; Chandra & Thompson, 2000; Handy, 2005). Criticisms about the relevance of traditional concentric and sectoral models of urban transformation during the postwar years stimulated discussions and subsequent formulation of alternative theories such as the Multiple-nuclei model (Harris & Ullman, 1945) of urban change. One major criticism to the concentric and sectoral models holds that these models are no longer relevant in describing urban form during postwar years even though the CBD is still a major center of social and economic relations in a given locale. The multiple nuclei model of Harris and Ullman (1945) provides a notion that as city grows and expands, similar and complementary activities tend to group together, thus, creating the formation of new sub centers. Over time, these sub-centers act as nodes from which a certain land use organization and pattern develops. This notion has been empirically tested and findings have shown that the multiple nuclei model provides a 56 better description of the urban transformation process that is more in sync with contemporary metropolitan form and structure. As urban landscapes evolved into a more complex systems and new perspectives have dominated in the analysis of such systems, the three classical human ecological models of Burgess, Hoyt, and Harris and Ullman have continued to yield useful results for understanding urban growth and land organization (Shearmur & Charron, 2004). They provide important insights for how individuals, households, and jobs are spatially distributed and the processes that propagate the distribution. Further, these models reveal the social and implicitly, the power structure, in as much as the_spatial structure of a metropolitan landscape. Overtime, however, sociologists have advanced alternative perspectives that recognize forces of urban growth and sociospatial processes beyond the ideas of competition, dominance, and succession as structures of the classical human ecological perspective. Some alternative models of human ecology reject the biological orientation of classical human ecology and tend to dismiss conflict as a driving mechanism for sociospatial and growth patterns in metropolitan landscapes (Hawley, 1950). Others represent a more holistic and synergistic model that addresses questions of sociospatial change and other processes of human systems from an integrated social and environment perspectives. A number of human ecology models recognize the importance of population, environment, and technology but also stresses organizational dynamics as a critical interacting dimension shaping socio-spatial and other processes of human systems (Duncan et al., 1959; Duncan, 1964; Dietz & Rosa, 1994; Dunlap et al., 1994). 57 Essentially, this theoretical approach highlights the interrelations between social system and natural processes. For example, the population, organization, environment, and technology or POET (Duncan, 1964) model represents a holistic approach that emphasizes these four interacting and synergistic components of POET as dynamic causal forces effecting changes described above. Human Ecology within Geographic Inquiry While human ecology is a well researched topic in the sociology discipline, the literature on human ecology in geographic inquiry also reflects an extensive engagement of geographers in the theorization and application of the human ecology subject. Indeed, similar to sociologists, the idea of human ecology as a holistic approach has been a well- recognized interpretation of human ecology in geographic inquiry. However, although geographers recognize human ecology as an integrative study of human-environment relations (Barrows, 1923; Gross, 2004), the early conceptualization of human ecology in geography has had strong environmental deterministic orientation. Goode (1904), for example, defines human ecology as “the geographical conditions of culture” (p. 584) and asserts that human ecology “passes beyond geography (p. 584).” Huntington also casts human ecology towards a more physical and environmental deterministic interpretation as exemplified in his work on different climatic regions on civilization (Gross, 2004, p. 589). In the 19203, a shifi in interpretation from a primarily environmental deterministic to a more holistic orientation has been made partly as a corrective effort. Barrows (1923), indicates “geography as human ecology” and defined human ecology as “the objective of geographic inquiry and 58 geographers’ inquiry must be in the pursuit of the mutual relations between man and his natural, the physical and the biological aspects, of the environment” (p. 3). Thus, it appears that a paradigm shift within the geography discipline with respect to the conceptualization and application of human ecology occurred. As the extensive literature shows, many geographers were engaged in many ecological studies and human ecology certainly had a niche within this body of studies. According to Zimmerer (1996), geographers adopt and apply five ecological approaches in the study of interrelations among organisms and the environment. These include: 1) human ecology-including natural hazards approach; 2) cultural historical ecology-from the Sauerian school; 3) systems ecology-a subset of human ecology; 4) adaptive dynamics ecology-sometimes referred as cultural ecology, and 5) political ecology. These different genres of geographical ecology indicate diverse ways that geographers frame their analysis, with each approach tied to particular methods, subject of interest, and epistemological perspectives. ln social geography, human ecology continues to be prominent particularly within the medical geography sub discipline. Accordingly, “the social model of human ecology is said to survive in geography in the form of human ecologies of disease” (Del Casino & Marston, 2006). This human ecology model approaches vulnerability and diffusion of disease from a multi dimensional perspective and asserts that relationships between population (biological selves), habitat (natural, social, and built environments), behavior (beliefs, social organization) and technology shape disease ecology (Meade and Earickson, 2000). These components of human ecology of disease, in some ways, parallels with the human ecology of Park (1936), which comprises four co-evolutionary 59 and multi-dimensional components described previously. Given the holistic, integrative and multidimensional orientation that human ecology is conceptualized in the geography and sociology disciplines as described above, this study adopts a human ecology framework that recognizes the relevance of these (environment, population, and behavior) components in understanding patterns of decentralization. Akin to the human ecology framework proposed by Park (1936), and Meade (1977) and Meade & Earickson (2000), the human ecology framework adopted in this study recognizes the essence of the environment, population, and behavioral (EPB) forces shaping patterns of decentralization. Essentially, the pattern of decentralization in a metropolitan area is conceived of as a pattern shaped by the interacting environment, population and behavioral factors in a given region. Thus, the environment, population, and behavior model of human ecology is a relevant model for analyzing the transformation of the urban landscape, particularly in explaining racial differences in decentralization in metropolitan areas. The human ecology framework offers a highly inclusive approach despite inherent differences in applications between disciplines and articulation of some of the key components of the framework. For example, Catton (1994) asserts that sociologists and geographers differ in their interpretation of ecological concepts. Specifically, geographers and sociologists have different interpretations and conceptualizations of environments. For geographers, environment means the physical and biotic aspects and they emphasize the integration of the physical and social elements in the analysis of human behavior, processes, and phenomena. For sociologists, specifically the ecological school of Park et al. (1925), the environment meant the social and cultural surrounding a person or group, not necessarily 60 the land water, air and biotic factors of the environment (Catton, 1994; p. 84). Catton basis this distinction on the projects that sociologists pursued, which include extensive work on urban spatial structure and mapping of crime, ethnicity, and other economic, social, and demographic variables. However, Catton clearly misses the original interpretation of human ecology model, which specifically identifies the physical/natural environment as one of the four interacting components of the classical ecological model, and to reiterate include: population, artifact (or the technological culture), customs and beliefs (or the non-material culture), and natural resources (Park, 1936; p. 15). Regardless of differences in interpretation of key components of the human ecology framework, one common view for scholars from both geography and sociology disciplines is that human ecology is a holistic and inclusive approach, and is a relevant framework for understanding complex processes of human systems such as urban growth and decentralization in metropolitan areas. Understanding Patterns of Decentralization using a Human Ecology Framework The pattern of decentralization in metropolitan areas is a result of dynamic, complex, and interdependent interactions and relationships between people and the environment. Because people structure and interact with their environment and environment facilitates in the formation of human behavior, an understanding of how they interact and results in decentralization necessitates viewing decentralization from an integrated perspective. Viewed in this vein, human ecology described in the previous section, is a relevant framework for structuring an analysis of the relationship between local roads (spending and stock) and the decentralization of people in metropolitan areas 61 while accounting for population (socio-economic characteristics), behavior (social structure), and the environmental (local roads, locational) factors. Therefore, this dissertation adopts human ecology as a methodological framework. The framework structures an analysis of the relationship between local roads and patterns of decentralization as a phenomenon resulting from the dynamic human and environment relations. Further, it enables an analysis that integrates three theoretical perspectives of residential mobility and locational outcome using the segregation and residential mobility literatures within the social geography sub discipline. These perspectives include: ecological or spatial assimilation, neighborhood preference and place stratification perspectives. As reviewed in Chapter Two, these perspectives and their empirical application provide relevant background for the development of the conceptual and empirical models of this dissertation research. The review of these perspectives helped identify the proposed causal factors of patterns of decentralization in metropolitan areas. The Conceptual Model Following the theoretical perspectives for decentralization and residential patterns described in Chapter Two, the ecological or spatial assimilation, place stratification, and neighborhood preference theoretical perspectives are weaved into the role of local roads and government policies on local roads development. The integrated perspective enables a broad-based conceptual human ecology framework of Environment, Population, and Behavior (EPB) that is relevant for explaining the relationship between local roads and patterns of decentralization by race. The model of decentralization by race weaves 62 concepts of local community attractiveness via roads stock, roads spending, and distance from the CBD as amenity and locational input factors, behavioral concepts via neighborhood preference and racial discrimination variables, into the ecological concepts of competition and spatial assimilation via socio-economic status as spatial mobility factors. Figure 3.1 describes an Environment, Population, and Behavior (EPB) human ecology conceptual model that reflects three critical and interrelated components that underlie patterns of decentralization by race in metropolitan areas. These model components reflect the underlying theoretical explanations of population decentralization that recognize the relevance of local roads as an environmental amenity variable as well as locational factors measured by distance from CBD (i.e., distance from downtown Detroit) and other existing population (i.e. socio-economic factors) and behavioral (i.e. neighborhood preference and racial discrimination) explanations of the decentralization phenomenon. 63 Population Component Socioeconomic Status (Income, Education) V Patterns of Decentralization by Race Built Environment Component Behavior Component Amenity and locational factor Attitude/Preference (Local roads spending, location (White homeownership, proportion of non- preference—distance from CBD) whites) Figure 3.1. A Conceptualized Relationship between Local Roads and Population Decentralization Based on the theoretical explanation of the relationship between local roads spending and differential levels of decentralization of people by race, the conceptual model can be specified as: D,-, = f (ROADit, POP), , SEC” , 83); where, (3.1) D), is an indicator of decentralization (Population density change, percent change in relative concentration or representation of non-whites using the Location Quotient approach, and non-white population density change) at the local level i in a given time t; ROADi, is local roads stock and spending and represent environmental amenity due to government behavior effects on decentralization; POP” is the population characteristics or spatial assimilative factors of the community via the socioeconomic characteristics; 64 SE C), represents neighborhood preference and place stratification factors via demographic composition and representation of white homeownership; a,- is the random error or the remaining variability in a given community i; and t denotes a time period in year. As Equation 3.1 shows, understanding the process of population decentralization is a complex matter and requires a multi perspective approach that recognizes population, behavior, and environmental factors as specified in the human ecological framework adopted in this study. Each component or dimension of the model is explained further in subsequent paragraphs. The conceptual model posits that the decentralization of people in metropolitan areas in general, and by race in particular, is shaped by past condition of the interrelated causal factors that reflect the multi-dimensional human ecology conceptual model adopted in this study. This means that lag value of the specified causal factors — population via socioeconomic characteristics, behavior via neighborhood preference and place stratification factors, and environment via local roads and spending, and locational factors —— explain the decentralization of people in metropolitan areas. Essentially, the EPB conceptual human ecology model highlights that patterns of decentralization are shaped by environmental factors, the competitive and assimilative capacity of a population group, and behavioral factors. The expectation is that different levels of participation by different racial groups should reflect these three conceptual components and their identified proposed explanatory factors. The model and the different components are described below. 65 Model Component 1 The Built Environment (Local roads spending, Local roads, Locational factors) The environment component of the human ecology model adopted in this study reflects the relevance of the built environment as a vital consideration for identifying selecting residential or business location. The choice of residential location is affected by many spatial and locational factors including the internal structure of the built environment, which is shaped by roads network. As described in the introductory chapter, local roads provide basic infrastructures for local communities and their development and maintenance to optimal standard are added amenities that affect intra and inter- community accessibility, property value, and quality of life particularly for the sense of safety that these evoke upon community residents and strangers alike. In communities where local roads investment is substandard, the quality of roads services is more likely compromised. Accordingly, low quality of road services affects the relative attractiveness of a given community for residential or job/industries relocation. Given the sensitivity of roads quality and services on investment patterns, local roads spending can be a critical component in community formation and growth. Local roads spending should affect the relative attraction and retention of people and industries. It follows that variability of local roads spending across communities in a metropolitan landscape should affect the structure of the built-environment, patterns of distribution of people, the density and intensification of land use, and the culture and lifestyle (behavior) that are promoted and upheld by the design and form of roads network established. Thus, local roads and the role of government spending are relevant 66 factors that are expected to contribute to the pattern of growth and decentralization of people in a given metropolitan area. Another factor that affects patterns of decentralization is locational attributes, specifically the relative location of communities with respect to a central business district (CBD). The relative location of communities, whether a central city, inner ring suburban, or exurban community, may provide an indication of relative attractiveness of such communities for residential and industrial relocation. Since suburban communities have become the destination communities for many individuals and businesses, it is highly likely that the location of community with reference to a CBD is an important determinant of pattern of grth and decentralization in metropolitan areas. These two factors local roads (stock and spending) and locational attributes are environmental conditions that individuals and businesses consider in relocation decisions. Patterns of growth and decentralization in metropolitan areas should reflect these two factors. Model Component 2- Population, Socioeconomic status (Spatial Assimilation Perspective) As presented in Chapter Two, patterns of decentralization by race reflect variations in individual’s or group’s capacity for spatial mobility as the ecological or spatial assimilation perspective asserts. This means that higher levels of socioeconomic status, measured in income, education, or occupation should increase the capacity of individuals and population groups for moving into suburban neighborhoods where relatively, better amenities and quality of life are often available. For minorities or non- whites, higher socio-economic status should enable them social mobility, subsequently, 67 spatial mobility. This means that minorities would have a greater Opportunity for participating in decentralization and eventually, assimilation with the majority white population group. Model Component 3--Behavi0r Social/Racial preferences (Place Stratification and Neighborhood Preference Perspectives) While spatial mobility is contingent upon socio-economic status as the ecological and spatial assimilation perspective asserts, certain behavioral conditions may facilitate or impede patterns of mobility of individuals and groups particularly those individuals and population groups who may perceive hostility from their potential neighbors in a residential context. Therefore, the participation of minorities in the patterns of decentralization should reflect the variation of these behavioral causal factors across communities in a given metropolitan region. As the neighborhood preference asserts, the demographic composition of a residential location. The demographic composition affects the relative attractiveness of a community for residential location. Therefore, the relative attractiveness of a given community should reflect preferences for either homogeneous or diverse communities. On the other hand, structural forces may constrain individuals or groups from participating in the decentralization process. As presented in Chapter Two, discrimination and prejudice in destination communities and other informal and institutional forms of discrimination are behaviors that impede minorities from relocating in communities where these behaviors are perceived to exist. Therefore, preference for certain demographic characteristics and structural forces should affect the pattern of decentralization in metropolitan areas. These 68 factors signify the relevance of behavior in the patterns of decentralization. More specifically, they provide alternative but complementary explanations to the spatial assimilation, and environmental or amenity-based explanations of patterns of decentralization. The conceptual model described above theoretically specifies the effects of the population, behavior, and built environment on decentralization of people in metropolitan areas. It specifically proposes that patterns of decentralization by race is explained by environmental factors or local roads (spending and stock), socio-economic factors or income and education, demographic composition or the percent non-whites, racial discrimination or proportion of white homeowners, and locational factor or diStance from a central business district. The conceptual model is tested in the context of the Detroit Metropolitan Area using cities and villages as units of observation. Hypotheses of the Study This research will test the following hypotheses: 0 municipalities with higher roads stock and road spending are expected to facilitate increases in population and that increase in population will contribute to the decentralization of people; 0 Communities with higher local roads spending and road stock, higher representation of non-white population, lower representation of white homeowners, higher income and education, and located increasingly away from a central business district are more likely to increase the representation of non-white population, and that increase in population 69 contributes to increasing level of participation of non-whites in the decentralization of a metropolitan area. Whether the two hypotheses presented are supported in the context of the Detroit MSA is the subject in the remaining chapters. The next chapter presents the empirical model of the relationship between local roads and decentralization. Informed by the literature on segregation and residential patterns, the empirical model of decentralization is specified, and is integrated into the human ecological framework adopted in this dissertation study. 70 CHAPTER FOUR: THE EMPIRICAL MODEL The Enviromnent, Population, and Behavior (EPB) human ecology conceptual model developed in this dissertation research and described in Chapter Three provides a rational for developing an empirical model of the relationship between local roads and decentralization. The empirical model highlights decentralization by race as a process shaped by improvements in the urban built enviromnent through local roads spending, and distance from the CBD as a locational factor affecting preference for either central city or suburban relocation. The empirical model also emphasizes socioeconomic status as population characteristic that determines spatial assimilation; demographic composition as determinants of an individual or a group’s preference for certain neighborhoods; and representation of whites’ homeownership as proxy for attitude of discrimination against certain population groups. The two variables, demographic composition and representation of white homeowners are behavioral factors affecting patterns of decentralization of people by race as the neighborhood preference and place stratification perspectives assert. Consistent with the conceptual model, the empirical estimation specifically involves testing for the effects of local roads (roads stock, road spending) on the differential levels of decentralization across population groups measured in non-white population density change and relative concentration of non-whites using the Location Quotient (LQ) approach. The model specifies that decentralization is a function of road spending and road stock, income, education, proportion of white homeowners, percent non-white population, and distance variables. The empirical model is developed using relevant studies of decentralization within the literatures in segregation and residential 71 llli de. 10C pattern presented in Chapter Two. The empirical model specifies causal factors of decentralization and estimates the model in the context of Detroit MSA. The empirical estimation is based on aggregate measures using the municipality (cities and villages) as units of analysis. l Chapter Four is organized into two sections. The first section describes the empirical model. The second lists specific aims of the dissertation study. Model Specification The process of central city out-migration as discussed above is shaped by complex interdependent factors involving environmental, population, and behavioral factors. The built environment and its attractiveness for household and industrial location contribute to local community growth. Therefore, government spending on local infiastructure should facilitate the attractiveness of a given community for household relocation. The importance of local roads in a community’s attractiveness for residential relocation goes beyond spatial benefits (Yago, 1983). Local roads impact residents’ quality of life in terms of their everyday experiences with traffic and congestion, pedestrian safety, pollution and noise (Marans & Sheehan 2003). Moreover, local roads enable connectivity and walkability. On the other hand, local roads are used to separate people into certain neighborhoods and increase the social stratification by race, class, and income (Grannis, 1998). Therefore, local roads can be seen as facilitators of decentralization but at the same time deterrents to residential integration. It follows that local roads and the quality of the service these provide are desirable amenities that shape 72 mobility and accessibility patterns in a given region with few exceptions. The empirical evidence that this study hopes to generate should shed insights into the impacts of roads on the decentralization patterns in metropolitan areas. Aside from the influence of roads in the development of the built environment, population characteristics (socioeconomic factors) determine capacity for spatial mobility of individuals and households and are very critical in explaining patterns of decentralization. Socioeconomic factors such as income and education determine social mobility, hence, spatial mobility as the spatial assimilation perspective asserts. On the other hand, evidence suggests that race distorts the ecological theory and the stark spatial and social separation between majority whites and people of color in residential spaces exists regardless of socioeconomic status (Alba & Logan, 1993; Darden, 1989; F arley, 1979; Madden, 2003). Accordingly, blacks with higher level socioeconomic status are still segregated in suburban areas in as much as those blacks who are living in central cities (Darden, 2003; Darden & Kamel, 2000). Therefore, the empirical evidence shows that while ecological theory provides a consistent explanation for the spatial distribution of people across metropolitan landscapes for some groups, it cannot fully explain alone the differential levels of decentralization of people and their locational pattern. Preference for certain locations on the basis of demographic characteristics, and racial discrimination and prejudice explain the different levels of decentralization by race. To determine the explanatory power of these variables on decentralization, researchers have often used proxy variables in lieu of more direct measures that are not easily available unless a sophisticated approach such as paired-testing is employed (National 73 Research Council, 2002). The percent non-white and proportion of white homeowners are used as proxy variables of the neighborhood preference and place stratification explanation of decentralization. These variables are approximation of preference for either homogeneous or diverse residential location, and proportion of white homeowners as measure of racial discrimination. It follows that the spatial distribution of communities with better local roads stock and investment may reveal the location and direction of growth in a metropolitan area. One can therefore explain, via regression analysis, the causal relationship between the differential levels of decentralization and local road spending and road stock (road density) while accounting for income and education as ecological or assimilation variables, percent non-whites as the neighborhood preference variable, and percent white homeownership measured as proportion of white homeowners for the housing discrimination as a place stratification variable. A distance variable is included in the model to account for the effects of location as a determinant of preference for either central city or suburban location. More specifically, it measures the separation effect of distance on the pattern of decentralization of population groups based on race. A fully specified model of decentralization is presented below. ADecentralization it =f(Road spending and density”. 1);, Income“. 1); ,Education(,.1),- , %Non-whites(,.1),~, Proportion of white home owners(,.1),- , Distance, 8;); where, (4.1) ADecentralizationit uses indicators including percent change in total population density, percent change in non-white concentration, and percent change in non-white density for 74 community i at a given time period t, between 1980 and 1990 which are years that many central cities in the Northeast and Midwest have had drastic decline in population. These are indicators of local community attractiveness or absorption capacity of a given community; Road spending and road density“. 1);, are amenity and policy effects variables including state allocated road fimding, locally-raised road funds, and local roads density; Income“. 1)i and Education“. 1);, are variables for socioeconomic status that affect spatial mobility; % Non-whites". 1); is a variable for neighborhood composition reflecting preference for either homogeneous or diverse community; proportion of White home owners(,.1),- is a proxy variable for housing discrimination; and Distance is a variable for locational factors that determine preference for either central city or suburban relocation; e,- is random errors or remaining variability, and t-I represents previous or lagged values of variables in the model. Using the standard multiple regression and spatial regression approaches, the empirical model estimates decentralization using three measures of decentralization described previously, as a function of lag values of local roads spending (state-allocated and locally-raised) and local road density while accounting for socio-economic factors income, education, percent white homeowners, percent non-whites, and distance from the CBD. The multivariate model specification provides an estimate of the effects of local roads on decentralization in the context of the Detroit Metropolitan Area. The lag specification of the model accounts for the effects of past conditions or values of explanatory variables on each of the three measures of decentralization. The lag specification is used recognizing that the effect of these explanatory variables on pattern 75 of decentralization takes some time. The empirical model is tested in the context of the Detroit Metropolitan region to accomplish the following specific aims of the study. Specific Aims Having specified the empirical model, the study aims to: 0 develop a conceptual model to explain the relationship between local roads and decentralization, and test this model in the context of the Detroit Metropolitan region using a human ecology methodological framework, accounting for income and education as ecological and spatial assimilation variables, percent non—white as neighborhood preference variable, proportion of white homeowners for place stratification variable, and distance between a municipality to the Detroit CBD as a spatial or locational preference variable. 0 characterize the pattern of decentralization in the study region using three measures of decentralization, which include: 1) percent change in population density of the general population; 2) the percent change in the relative concentration of non-whites; and 3) percent change in non-white population density, 0 characterize the pattern of local road spending across the region; and 0 determine links between local roads and patterns of decentralization for the general and non-white population while accounting for other proposed predictors including household median income, percent non-white with 76 college education, proportion of white homeowners, demographic composition, and distance from the CBD. The next chapter describes the Detroit Metropolitan Area as the case study area. It also describes the data and methods employed in the research, and the analytical approach. 77 CHAPTER FIVE: DATA AND METHODS The primary goal of this dissertation research is to understand the possible influence of local roads on the decentralization process in metropolitan areas within a social geographic inquiry. As described in Chapter Three, the research conceptualizes the relationship between local roads and decentralization using a human ecology methodological framework that integrates environment, population, and behavioral attributes as proposed explanation for racial differences in decentralization. To implement the empirical model described in Chapter Four, this chapter introduces the data, methods, and estimation procedures. The chapter is divided into three sections. The first section describes the study area and the general considerations for choosing the area, the study period, and the unit of analysis. The second section describes the variables, data used and their sources, data processing, and organization procedure. The third section describes the estimation approach adopted for determining the relationship between local roads and decentralization. A brief summary of the data and analytical approach end the chapter. The Study Area Since the latter part of the twentieth century, metropolitan areas in the US. have become home to more than 50 percent of the entire population in the U. S. By 2000, metropolitan areas absorbed about 80 percent of the entire U. S. population of 281 .4 million residents, and have become increasingly characterized by distinct demographic distribution (Hobbs & Stoops, 2002; p. 33). 78 All across the US, 75 percent of metropolitan residents are whites, while about 25 percent are non-whites (Hobbs & Stoops, 2002; p. 77). Indeed, non-whites, who are represented by blacks and all other individuals from other races, including foreign-born residents tend to have a strong preference for metropolitan locations (US. Bureau of the Census, 2000; Kent et al., 2001). Their presence and concentration in metropolitan areas, more specifically in central cities, makes a metropolitan area a relevant geographic context for understanding the different patterns of decentralization of the general and non-white population groups. The possible causal relationship between local roads and population decentralization is examined in the context of the Detroit Metropolitan Area in Michigan as the case study area. Also known as the Detroit Metropolitan region or the Detroit Tri-County Area, the Detroit Metropolitan Area comprises the Wayne, Oakland, and Macomb counties with 131 communities located within this region. These communities include 75 cities, 15 villages, and 41 townships with Northville and Richmond straddled between two counties (Figure 5.1). 79 Sour “- Washtenaw Legend — Interstate Highway D County 0 25 5 londfles F+4—+4—+4—+4 Figure 5.1 The Study Area Source: Developed by the author from accessible maps in Michigan Geographic Data Library, Center for Geographic Information. 80 General Considerations for Selecting the Case Study Area While there are many regions that are relevant for determining the causal relationship between local roads and the decentralization of people by race, the Detroit Metropolitan region offers a particularly more compelling context for unraveling different causes of decentralization. The Detroit Metropolitan region represents the most decentralized region in the state of Michigan with an unprecedented rate of suburbanization of the white population. Also, the region is characterized by uneven development, a high incidence of concentrated poverty in the central city, and a residential pattern that starkly separates people by race and class. Aside from the population dynamics, land consumption in the region far outpaces population grth by an average ratio of 13 to 1 between the years 1960 and 1990. This means that the land consumption in the region was 13 times faster than the region’s population grth between those years (Michigan Land Use Leadership Council, 2003). The distinct demographic distribution, unprecedented land consumption, and a sustained uneven development, incidence of concentrated poverty makes the region a highly relevant context for understanding complex causes of decentralization. These circumstances in the Detroit Metropolitan region require an understanding of the role of government policies, particularly policies on local road development that are more likely to have contributed to the decentralization process. As the most urbanized region in the state, the Detroit Metropolitan region has an extensive road infrastructure. A total of 17,949 miles of primary and local roads, trunk lines, and freeways are developed and maintained by three separate county road 81 dc m Re leg] the a . tlp berm: commissions in Oakland, Wayne, and Macomb counties.l This roads stock represents 65 percent of the total roads in southeast Michigan and show the intensity of the built enviromnent in the region. In light of the pattern of road development and the significant population shifts that have been occurring in the region, the Detroit Metropolitan region offers an excellent opportunity for unraveling the influence of local road spending and decentralization. The analysis of the relationship between these processes reveals additional insights into the deep inequality in the allocation of road funds across communities and its possible link to the decentralization process. A more detailed description of the circumstances in Detroit Metropolitan region is presented in the next paragraphs. Regional Population Trends The Detroit Metropolitan region is the most urbanized and populous region in southeast Michigan with a land area of 1,967 square miles and 183 square miles of water (SEMCOG, 2002). Population shifts in the Detroit Metropolitan region reflect the dynamic growth and development in the region over time as Figure 5.2 shows. The region experienced an unprecedented population grth and development particularly in the first three quarters of the twentieth century. In the 703 and 803, however, the region experienced population decline at the rate of 3.8 between 1970 and 1980, and 3.3 percent between 1980 and 1990. But by the 19903, the region gained population by 3.3 percent, which was equivalent to what it had lost in the previous decade (Hobbs & Stoops, 2002). ' This information is available at the Southeast Michigan Council of Government website at http://www.semcog.org/Data/Apps/comprof/transportation.cfm?cpid=8999 last accessed on August 15, 2009. The southeast Michigan region, which comprises Wayne, Macomb, Oakland, Washtenaw, Monroe, Livingston, and St. Clair counties, has 28,000 miles in road stock. 82 Current estimates indicate that the Detroit Metropolitan region 0.78 percent of its population between 2000 and 2008. Wayne County lost an estimated 4.2 percent of the entire metro population (SEMCOG, 2008). Indeed, as of July 2008, the Southeast Michigan Council of Government estimated that some 86,020 persons have left Wayne County for other locations since 2000 (SEMCOG, 2008). While the population trend in the Detroit Metropolitan region as a whole may suggest a grim condition, the intraregional dynamics presents a different context. While Wayne County experienced a significant population loss since 2000, Oakland and Macomb counties experienced population gains at the rate of 0.9 and 5.6 percent, respectively. It follows that the population loss in the Detroit Metropolitan region is largely attributed to the losses in communities in Wayne County, particularly the city of Detroit, which has experienced a steady population decline since the 19503 (SEMCOG, 2008). 4,500,000 4,000,000 1 5 3,500,000 1 :3 3,000,000 32,500,000 1 3 2,000,000 - 5 1,500,000 ~ .3 1,000,000 - 500,000 1890 1900 1910 1920 1930 1940 1950 1960 1970 1900 1990 2000 2010 Year Figure 5.2 Detroit Metropolitan Area Population Trend, 1900-2008 Source: Southeast Michigan Council of Governments (2002, 2008) 83 ml ice He, up dt‘q‘ llm The City of Detroit. The City of Detroit is located within Wayne County and is the largest city in the region and the State of Michigan with 951,270 residents as of 2000 (US. Bureau of the Census, 2000). As one of the aging industrial cities in the Midwest, the city of Detroit has been experiencing a significant population and job losses. As of the 2008 population estimate, the city has 860,521, which was less than half of the population in the 19503 when the city experienced its highest centralization point of 1.85 million people (SEMCOG, 2008). The significant population 1033 in the city resulted in high rental and home vacancy rates, making the city of Detroit America’s second most abandoned city (Greenburg, 2009). The high rate of housing vacancy and abandonment in Detroit is one of many manifestations but also a cause of other more complex and reinforcing outcomes of decentralization. Land use change and uneven development, economic and residential segregation, joblessness, and the concentration of poverty have all become major distinguishing features for the city of Detroit. Essentially, the steady decline in the city created many economic, social, and environmental woes that are disproportionately experienced by different segments of the metro population. Land Use Change and Pattern of Uneven Development A significant outcome of the unprecedented population growth in the city of Detroit during the first half of the twentieth century was the centrality of the pattern of development in the region. Detroit attracted people from across the country and around the world due to available jobs in the car manufacturing and related industries (Darden et al., 1987; Teaford, 1993). During the second half of the twentieth century, however, the 84 C011 Cor squa {our 1610 dam: 30051 the in 0000‘ 160110 1993). P311130. need 0 111mm, . concentration of housing production and jobs shifted toward the peripheries. Consequently, the metropolitan landscape significantly changed. In the 19903, an estimated 33 percent of the region’s land area of about 1,967 square miles was already urbanized (Limoges, 2001). This urbanized area was then about four times the size of the urbanized area in the 19503. This significant change in land use reflect primarily, the conversion of tracts of land into urban uses in response to increasing demand for housing, infrastructure, and other institutional support services. Subsequently, the increasing suburban development, significant industrial shift toward the fringes occurred, followed by the retail industries (Darden et al., 1987). Thus, the Detroit Metropolitan region was transformed from a highly centralized to a less centralized urban region and has since been characterized by “edge cities” (Garreau, 1992). People and capital flow towards the fiinges of the city became the dominant pattern of mobility for people and industries in the region, leaving the central city in dire need of economic and physical revitalization. Income Disparity The Detroit Metropolitan region is characterized by a deep disparity in income between counties and cormnunities. For example, the per capita income for Wayne County in 2000 was $20,058, which was below state level per capita income of $22,168. Oakland and Macomb counties, on the other hand, were both above the state level with $32,534 and $24,446, respectively. The median household income of Bloomfield Hills City in Oakland County was $105,000 and was ranked 17th in the country. Birmingham City in Oakland County was $37,061. On the other hand, Ecorse and Dearborn cities in 85 d1 10:1 the Wayne County had a per capita income of $9,781 and $21,488, respectively (US. Bureau of the Census, 2000). Refer to Figure 6.6, which illustrates the trend of income distribution in the region by communities and with respect to distance from the CBD of Detroit. This income disparity across communities in the region reflects the spatial distribution of people by race in the region. Racial Segregation Residential segregation in the Detroit Metropolitan region is one of the highest in the county with blacks or African Americans, experiencing the highest level of segregation from whites. This means that blacks are segregated the highest from whites compared to Asians, Hispanics, and other racial groups (Darden et al., 1987; Rusk, 2003). The pattern of high levels of segregation between blacks and whites in the Detroit region has been consistent. Between 1940 and 1970, the white-black racial segregation in the Detroit Metropolitan region was high, with index of dissimilarity that ranged from 83.7 to 88.9 (Darden et. al., 1987; p. 87). A decrease in segregation was noted in the 19803 (85.8), down by 3.1 percent from the previous decade. Similarly, Rusk (2003) indicated a decline in segregation in the region when he found a dissimilarity index of 81 in 2000, down by 2 percent points from the previous decade (1990). These decreases in levels of segregation, however, do not readily translate into improvements in the quality of life especially for blacks. These population groups continue to experience high levels of isolation not just in the residential space but in educational and other spaces of opportunity. 86 School segregation is markedly high in the Detroit Metropolitan region and is one of the highest in the country (Frankenberg et al., 2003; Rusk, 2003; Orfield, 2002). The index of dissimilarity was 82 percent in 1997 (Orfield, 2002; p. 52) and 89 percent as of 2000 (Rusk, 2003; p. 40). These indices simply show that the demographic composition of schools closely resembles the residential patterning in the region. They reveal not just the inequality in residential and educational opportunities but also disparities in access to and participation in jobs and other opportunities. In essence, residential and school segregation are inextricably linked with patterns of job and workforce distribution in the region. Job Distribution Job distribution in the Detroit Metropolitan region is highly decentralized and is one of the extremely decentralized employment centers in the country (Glaeser et al., 2001). Across 100 largest metropolitan areas in the country, an average 22 percent of the jobs are located within 3 miles of the CBD while 35 percent are located beyond 10 miles of the CBD. In Detroit, only 5 percent of the jobs are located within 3 miles while 78 percent are located beyond 10 miles of the CBD (Glaeser et al., 2001; p. 5). Further, only 22 percent of jobs are located within 10 miles, which is far below the national average of 65 percent (Katz et al., 2003). Indeed, while Detroit was still the leading employment center in the Detroit Metropolitan region in 2000, its share of the region’s employment has dropped from 38 percent in 19703 to 13 percent in 2000 (SEMCOG, 2002). In light of these circumstances in Detroit Metropolitan region, the region has become associated not for its production of the Model Ts that put the city on the map and 87 the cm 100 hr. 10 b1 ng lie n incre lOm H the minds of people around the country and the world, but for its production of edge cities (Garreau, 1992). In Detroit, the centrality and function of cities in the monocentric, modern period became increasingly superseded by multi-centric urban form as new developments — shopping centers, office complexes, schools and other institutions — in the suburbanized areas created new patterns of how people live, work, and play in the metropolitan region. Given the situation in the Detroit Metropolitan region, there is a critical opportunity for studying mechanisms and processes underlying income disparity, segregation, and patterns of decentralization. This research aims to contribute to an understanding of these processes by examining the effects of local road spending on decentralization and how government policies may have sustained these effects over time. To understand these effects, the dissertation research carefully identifies the geographic and temporal context, unit of analysis, variables and measurement, data, methods and analytical approach. These are presented in subsequent sections. The Study Period and Communities The analysis of the relationship between local roads and decentralization focuses between 1980 and 1990, which were years that decentralization in major cities continued to be prominent, particularly in the Midwest (Berube & Forman, 2002; SEMCOG, 2002). Figure 5.2 shows the population trend in the Detroit Metropolitan region and highlights the marked decline in the region’s population between 1970 and 1990. The steady increase in the region’s population prior the 703 is noteworthy. It confirms the region’s dominance in attracting people, and as a center of the car manufacturing industry in the 88 country. Whether the change in population trends was affected by government policies on local roads raises questions about the unintended consequences of government decisions. By focusing on the decade of distinct population decline in the region, the study presents a critical opportunity for determining how government policy contributed to the pattern of decentralization. The analysis focuses on 88 cities and villages, out of 131 communities that comprise the region. Forty one (41) townships were excluded from the analysis because townships do not have road jurisdiction in Michigan and are therefore, excluded in the distribution of government road funds. Appendix A lists the cities and villages in the study region. The Unit of A nalysis and Observation The relationship between local roads and population decentralization is examined using the municipalities (cities and villages) as units of analysis. The study then makes generalizations on the relationship between local roads and decentralization using information that best characterize and measure the pattern of decentralization and its proposed causes at the municipality level. The municipality is the finest geographical unit that local roads stock and spending variables are documented, particularly in the State of Michigan (Michigan Department of Transportation Series Report No. 139 and 162). Therefore, the analysis of the impacts of roads on the decentralization process is limited at this level of aggregation. 89 Variables and Measurement To reiterate, the empirical model of the relationship between local roads and decentralization in metropolitan areas and other hypothesized predictors of decentralization within a social geographic inquiry specifies: ADecentralizationit =f(Road spending and density(,_1),°, Income(t.1),°, Education (t. 1);, %Non-white3(,_1),', Proportion of white home owners(t_1),-, Distance, 8;); where, (5.1) ADecentralizationit uses indicators including percent change in total population density, percent change in non-white concentration, and percent change in non-white density for community i at a given time period t, between 1980 and 1990. These are indicators of local community attractiveness or absorption capacity of a given community; Road spending and road density(,.1),-, are amenity and policy effects variables including state allocated road funding, locally-raised road funds, and local roads density; Income(t_1),- and Education(,_1),-, are variables for socioeconomic status that affect spatial mobility; % Non-whites”. 1),- is a variable for neighborhood composition reflecting preference for either homogeneous or diverse community; proportion of white home owners(,_1); is a proxy variable for housing discrimination; and Distance is a variable for locational factors that determine preference for either central city-suburban relocation; e,- is random errors or remaining variability, and t-I represents previous or lagged values of variables in the model. The selection of variables in the empirical model was guided by the existing literature on decentralization within the residential mobility and segregation literature 90 domains. The model is tested to determine the decentralization of the population in general, and the differential levels of suburbanization between races in particular using population density and concentration of non-white population as dependent variables. Each dependent variable is regressed on local roads stock and spending, income, education, percent white homeownership, percent non-white, and distance between a central city and community as independent variables in the proposed empirical model. The Dependent Variable Population Decentralization As presented in Chapter One, the decentralization in metropolitan areas is ofien described as a pattern of urban transformation characterized by an uneven population grth across the metropolitan landscape. A decentralized region exhibits a stagnant, slow growth, or a significant population decline in the central city resulting in a decreased population density on one hand, and an increase in population and population density in communities outside of the central city on the other. Although many indicators of decentralization have been identified (Galster et al., 2001; Ewing, 1997; Lopez & Hynes, 2003), previous studies have consistently indicated the relevance of population density used either singly (Lopez & Hynes, 2003) or in combination of many other dimensions (Galster et al., 2001; Ewing, 1997). A conventional approach for assessing patterns of decentralization is by estimating a population density change (an increase or decrease) or density gradient within a metropolitan landscape (Jordan et al., 1998; Mieszkowski and Mills, 1993; Carlino & Mills, 1987). A decrease in population density in a central city accompanied by an 91 increase in population density outside the confines of the city demonstrates a decentralized pattern of growth in a metropolitan area. Population Density Change. A simple equation of population density change in a given community (6. g. city or village) i between 1980 and 1990 is presented in Equation 5.2. The equation specifies population gains, when the rate of change is positive and a population 1033 if otherwise. Further, it assumes that the land area is the same between 1980 and 1990. Equation 5.2 also suggests the attractiveness of community i for residential location. A positive value indicates an increase in population for community i and may suggest that community i is a “destination community” in a given metropolitan region. On the other hand, a negative value indicates a population 1033 for community i, which may indicate the unattractiveness of community i for residential location. Population density change of community i takes the form: P - P - APOPDeniJ980—l990 = 01" - & Where (52) Am" 1990 Am“ 1980 APopDeni, 1980,1990 is the change in population density at community i between 1980 and 1990 or the change in number of individuals per unit area or space; Popi is population count or number of individuals in community i; and Areai is the total area (e. g. in square miles) of community i. Differential Levels of Decentralization by Race. Equation 5.2 provides a general measure of the population dynamics in the region. The population dynamics is further understood by isolating levels of decentralization of people by race in metropolitan areas. It does so by specifically measuring the relative concentration or representation of the 92 non-white population group across communities in the region using the Location Quotient (LQ) approach. The Location Quotient (LQ) is an approach in Economic Base Analysis (EBA) that has been increasingly adopted in describing patterns of demographic and socio- economic processes in metropolitan landscapes, including residential and segregation patterns (Chung & Brown, 2007; Brown & Chung, 2008; Ray & Bergeron, 2007) and in crime incidence analysis (Zhang & Peterson, 2007; Guhathakurta & Mushkatel, 2000). The LQ measures the concentration of the phenomenon of interest such as the homogeneity or diversity of a population group in a particular locale (i.e. a block, census tract, village, and city) relative to a larger reference areal unit. The value of LQ ranges from less to more than 1 (0 - 00). A value of the LQ that is equal to 1 indicates that the concentration or representation of a particular population group is the same to that of the larger reference unit; a value of less than 1 indicates an under representation of the population group; and a value of greater than 1 indicates an over representation or concentration of the population group relative to the reference or larger areal unit. Unlike the traditional global indicator of segregation such as the dissimilarity index (DI), the LQ characterizes the local pattern of concentration of a particular population group (e. g. non-whites) with respect to the general population of that group in a larger areal unit (e. g. a metropolitan area). The variation in LQ across the landscape illustrates the distribution of low to high concentration of non-whites in the region. When mapped, the distribution characterizes a description of the relative representation of non- whites and may represent destination communities for the non-white population. 93 The change in LQ between two time periods indicates a relative change of the level of concentration of non—white population group in a given community between these periods and may suggest communities that have become “destination communities” for the non-white population group. Values derived from these measures of decentralization are mapped to determine the spatial pattern of grth and decline, the racial fabric across communities in the study region, as well as the change of the racial fabric across time. In this study, the Location Quotient change for community i takes the form: Emu-mi /_ " Popnon-W,i / Pop Total,i . _ POP TotaLi // / P op non - W. Metro * 1// Pop non-w, Metro . PapTotal, Metro 1990 ' P0P Total,Metro 1980 ’ ALQumran-1990 = P ‘ 0P non-w,i [ l)0!) Total,i ) ’ " P0P non-w, Metro J 3 Po PTota|,Metro 1980 where (5.3) ALwawgo is the Location Quotient change of community i between 1980 and 1990; Popmmw, ,-is the total number of individuals from the non-white population group in community i; PomeM is the total number of individuals in community i including the non-white and white (of Caucasian origin) population group; Popnomw, Mm, is the number of individuals from the non-white population group of the study region, and POPTota|,Me"-o is the total number of individuals in the entire study region as the reference unit. 94 1 01 Thus, Equation 5.2 is used to describe the dynamics and intensity of the distribution of the people in a given community. Equation 5.3 further captures the population dynamics by characterizing the concentration and representation of the non- white population goup for each municipality. Additionally, a third measure of the pattern of decentralization of non-whites, percent non-white population density is used. This measure enables the pattern of decentralization of the general and non-white population to be comparable. The Independent Variables Local Roads Spending and Stock As the conceptual model indicates, government spending on local roads is expected to facilitate decentralization in metropolitan areas. Improvements in the built environment due to local roads spending facilitates better intra-community accessibility, increases in property value, and benefits that have implications for quality of life. Higher local road spending rather than lower spending in communities, therefore, will more likely improve the quality of local road stock and services. One must acknowledge that state-allocated local roads revenue alone may not explain fully the mobility dynamics across communities and subsequently, patterns of decentralization. Road building is a complicated process and different sources of revenue may develop one or different road projects at a time. And, variation of road funds allocation could result in variation of local roads services, which have implications to the attractiveness of a given community for business or household relocation. Therefore, the variation of roads funds allocation could be tied to the variation of local roads services and would have implications for grth and land use change. 95 .11: 101 101' 101 1201 111 11g and Two variables are used in the model as independent variables for testing the influence of local roads on the decentralization of people in metropolitan areas. These closely connected variables are: l) the per capita local roads spending allocated by the state government or the Michigan Transportation Fund dollars and the locally-raised road funds, and 2) the local road stock in miles. The per capita local roads spending in a given year is calculated by dividing the total road dollar allocation for the community by the total number of people, resulting in a per person dollar road funds/spending variable. A road density is measured by dividing total local road miles of the combined major and local street by land area in square miles for each city and village in the study area. Both per capita dollar spending and road density are used in the model. To understand local roads allocation and spending in Michigan, a discussion that focuses on the sources of revenue for local roads development across the study communities is necessary. This is discussed in the next subsection. Sources of Revenue for Local Roads Development and Maintenance. In Michigan, as in other states, the allocation of the Federal and State transportation revenue for transportation development at the State and local levels is a complicated matter (Cadot et al., 2006). In terms of roadways expenditure, Federal monies are earmarked for highways and local roadways development with guidelines on how funds are to be used and what government bodies or entities are eligible to receive them. At the local level, the operating funds for the development and maintenance of roads come primarily from the Michigan Transportation Fund and locally-raised revenues. Other sources may come from matching funds and borrowings through bonds within the Act 51 guidelines. 96 The Michigan Transportation Fund. In terms of the State resources, only the Michigan Transportation Fund and the Transportation Economic Development Fund (Categories A and F) are accessible to local communities (SEMCOG, 2002). The Michigan Transportation Fund (MTF) formerly known as the Motor Vehicle Highway Fund is the primary revenue for the development of roads and transportation networks in the state of Michigan. The MTF is generated through the motor fuel taxation, vehicle registrations, and sales of auto parts. MTF revenues are distributed following an “external” (distribution to the MDOT, counties, and cities and villages) and “internal” (distribution/use within cities and villages) formula as prescribed in Act 51 of 1951 as amended under Michigan Compiled Laws MCL 247.651 Section 10. It was established through the Public Act 51 of 1951, which governs state appropriations for interstate and local highways and public transportation programs (Hamilton, 2003). The act was introduced through the House Bill number 42 on January 17, 1951 and was enacted on July 1, 1951 (Journal of the Senate, 1951). The motivation for the passage of Act 51 of 1951 can be traced back to the country’s interest in highway transportation to aid in defense and national development (Pohl & Brown, 1997). It grew out of the Good Roads Federation Study in 1947, which at that time, indicated “a need of $1 .5 billion dollars over a 15-year period to bring the entire highway system of Michigan -— State, county, and city roads to safe and tolerable standards” (Pohl & Brown, 1997, p. 9). Technically, the formula-based state spending on transportation in Michigan addressed the issues associated with the disproportionate or inequitable allocation scheme during the years prior to the enactment of Act 51. Prior to Act 51, the allocation scheme 97 was a matter of “political haggling” and funds for road development generally accrued favorably to rural interests (Warner, 1962). The enactment of Act 51 was a significant improvement to the road financing strategy and represented a major development toward an objective based formula free from political interference. Warner (1962) identified the significant contributions of Act 51 as: 1) The establishment of a new special fund, the Motor Vehicle Highway Fund (that was to become the Michigan Transportation Fund in later years), for isolating highway user revenues from general state revenues; 2) the introduction of road and street classification as a means for allocating user revenues; and 3) the promotion of cities to equal eligibility with the counties for user revenue grants. Indeed, the Act 51 policy provided a strong reform to the distribution mechanism underlying road allocation in the state. Since its creation in 1951 by the state legislature, the external formula has undergone a few changes (Welke et. al., 2000). Table 5.1 below shows the changes and the years in which they were made. The external distribution formula of 1985 is still applied to this date (Welke et al., 2000). Table 5.1. Changes in the Michigan Transportation Fund Distribution Formula Year MDOT (%) County (%) Cities/villages (%) 1952 44.0 37.0 19.0 1957 47.0 35.0 18.0 1972 44.5 35.7 19.8 1978 46.7 34.3 19.0 1982 41.9 37.4 20.7 1985 39.1 39.1 21.8 Source: Transportation Funding for the Twenty First Century, Welke et al., 2000 98 The “internal” formula guides the MTF distribution to cities and villages across the state of Michigan. Population and road stock (in miles) are used to determine the amount of dollars allocated for each place or community (SEMCOG, 2002). The amount allocated, therefore, can be affected by the increase or decrease of population and changes in road stock. It is also affected by broader factors such as the general MTF annual revenues through gas tax, vehicle registration, and sales of motor vehicle parts. Locally-raised Revenues. The second most important source of revenue for local roads development and maintenance come from the local govermnent sources through special tax levies, general fund appropriations, general obligation funds, and special assessment bonds. These revenues are used to match funds from other sources for local roads construction (Hamilton, 2003). Cities and villages could also avail of federal allocations in connection with designated high priority and demonstration projects specified by the US. Secretary of Transportation. However, the Michigan Transportation Fund is the major source of revenue for road development and maintenance at the local level. It is also used as payment for debt service for any borrowings that a city or village incurs provided it is in accordance with the Act 51 guidelines. One might question why road spending variable is included as one exogenous variable in the analysis of decentralization when in fact the MTF variable itself is a result of a formula that includes population and road stock. One might similarly ask why population and road stock could not have been used as explanatory variable of decentralization instead of state-allocated (MTF) road spending. Two pieces of information must be well-understood about the state-allocated (MTF) local road spending. 99 00‘ 11; p11 ;) H is lll1 11111 101 like First, the objective of the study is to examine the role of public policy on decentralization, which the state-allocated local road revenue (MTF) proxies. In examining such role, it is the policy instrument or mechanism that is directly linked to the process of interest (i.e. decentralization) and only indirectly accounts for road stock and population not vice versa. A direct test of the state-allocated local road spending and decentralization relationship is a direct test of the effects of policy, which one would not have observed using the population count and road stock information. Second, it is also important to recognize that policy makes the formula but they cannot change the variables that are linked through the formula (i.e. population and road stock). Given above, it is therefore relevant to use the state-allocated (MTF) local roads revenue not population and local roads as a proposed predictor of decentralization. One must also recognize that the state-allocated local roads and locally-raised revenues are the major sources of funding for local roads development. The impact of these on the decentralization of people in the study region is analyzed controlling for other identified predictors, which are presented in the following subsection. Income and Education Although a range of factors explain decentralization in metropolitan areas, the empirical evidence indicates income and education as predictors of the spatial mobility of people in metropolitan areas (Iceland & Wilkes, 2006; Timberlake & Iceland, 2007). The improvement in income and education among minorities, and adjustment to the “host” culture in the case of ethnic immigrants, facilitates suburbanization, and in turn, the likelihood of assimilation to the “major” population group (Massey, 1985). Further, 100 ’T") Ci income and educational attainment undergird the choices, preference, and the groups’ ability to access better residential amenities and economic opportunities. These socioeconomic factors facilitate the transition of the urban spatial and social landscape by processes of competition, invasion, succession, and enable adaptive capacity of minority population groups based on these “ability to pay” attributes (Park et al.,1925; Burgess, 1925; Hoyt, 1933). For this study, the income and education variables are drawn from the Census CD 1980 and 1990, which is a data source developed by the Geolytics Incorporated based on the Long Form census data file (Geolytics Incorporated, CD1980 & CD1990). Unfortunately data gaps still exist despite a well-organized and sophisticated resource such as the Census CD. These gaps are addressed in this dissertation research by using data from the National Historical Geographic Information System statistical and mapping data developed by the Population Center of the University of Minnesota. Two variables that assess capacity for spatial mobility of individuals and population groups are used. The income variable and education variables use household median income and proportion of non—white college educated individuals who are 25 years and over, and with at least four years of college education as determinants for the capacity of individuals and population groups for spatial mobility. Consistent with previous studies, these variables are identified as determinants of locational outcome and residential pattern in the metropolitan region as the spatial assimilation theory predicts. 101 Proportion of White Homeowners While income and education are relevant factors that explain the pattern of decentralization, these explanatory factors have become increasingly challenged in light of the persistent trends of differential levels of suburbanization across these groups. For example, trends of suburbanization for blacks or African Americans have dramatically improved in the last few decades but a pattern of high segregation between blacks and whites still persists. Such evidence challenges the “pure class” based explanation of decentralization. The income and education reasoning purported by spatial assimilation theorists simply cannot hold as the only explanatory factors for the differential levels of suburbanization across different population groups. An alternative explanation emphasizes racial discrimination and prejudice as important factors (Massey & Denton, 1993; Darden et al., 1987). The percent white homeownership has been used as a proxy for the discrimination and prejudice variables (Williams, et al., 2005). Percent white homeownership indirectly measures the incidence of housing discrimination and prejudice, which have become increasingly difficult to detect and measure since the passage of Fair Housing Act in 1968 (Massey & Denton, 1993; p. 59). Essentially, the FHA promoted anti-discrimination in local government and private sectors particularly in the real estate, and mortgage lending and insurance industries (Y inger, 1995). However, the extent that the law has successfully reduced discrimination and prejudice in the residential landscape has been contentious. Empirical evidence indicates a decline in segregation and increases in suburbanization for minorities and ethnic groups, but the pattern of high segregation 102 particularly for blacks and Hispanics persists. This reality mars any little improvement (decline in segregation) that has been achieved so far and increases the claims for the validity of discrimination and prejudice as dominant factors explaining patterns of decentralization and segregation in metropolitan areas. For this dissertation research, the proportion of white homeowners to the proportion of white population within each of the study communities is used as a proxy variable for the possible incidence of housing discrimination and prejudice. The variable represents a crude local approximation for housing discrimination as a factor explaining the low level of non-white decentralization. The white home ownership index ranges from a value 0 to 00, with 0 equal to no representation to high representation of white home owners in relation to the total white residents in a community. Percent Non-white Population An alternative explanation to the decentralization process in metropolitan areas highlights the relevance of neighborhood preference as an underlying cause. Generally, the empirical evidence indicates that different racial/ethnic groups tend to exhibit an “own race” preference for residential location (Clark & Fossett, 2008; Clark, 2009). Blacks, in particular express strong preference for integrated neighborhoods while whites express strong aversion to integrated and highly diverse neighborhoods. The empirical evidence indicates that whites are willing to move into a neighborhood with no more than 30 percent minorities. Blacks on the other hand, are willing to move into a community when there is a presence of 50 percent blacks and 50 percent from other races or ethnic 103 groups. These preferences shape locational outcome and the general pattern of suburbanization by different population groups. For this study, the percent non-white is a proxy variable for the neighborhood preference concept as an explanation to the differential levels of decentralization across population groups. The percent non-white measures the likelihood of other non-whites to relocate in a community based on the racial composition. It is plausible to predict that communities with a higher concentration of non-whites would attract other non-white residents than those with lower concentration of non-whites. Distance from the Central Business District Aside from the proposed determinants of decentralization described above, the distance variable enables an analysis of the changes in the distribution of people and intensity of land use across the metropolitan landscape from a monocentric framework. The distance from the CBD measures locational attributes and the extent of spatial separation between communities (Mieszkowski & Mills, 1993), which are proxy variables for the significance of geographical and spatial considerations that affect locational decisions (Belden et al., 1998; Burchfield et al., 2005). The distance effect on the decentralization process in the study region is measured in terms of areal distance or a Euclidean measure of separation between the Detroit CBD and each study community. The distance variable is derived by measuring the centroid to centroid distance using the Hawth’s Tools ArcGIS extension in ArcMapTM 9.1 (Beyer, 2004). This distance variable is used in the regression model. 104 Data and Data Selection To estimate the empirical model, data preparation including data selection, collection, processing, and integration procedures were undertaken. Three sets of data were needed to develop and test the causal relationship between local roads and the decentralization process. These include data on 1) demographic and socioeconomic characteristics, 2) the roads spending and road stock, and 3) GIS shapefiles for describing patterns of decentralization, and estimating spatial regression models. Data Collection and Processing Data were retrieved from existing sources. The demographic and socioeconomic data were extracted from the Census CD 1980 and 1990 (GeoLytics Incorporated). Other data were also extracted fi'om the National Historical Geographic Information Systems or NHGIS (2004) developed by the Population Center at the University of Minnesota. Both GeoLytics Incorporated and the NHGIS developed software and data products using data from the census of population and housing. Both organizations used the long and short forms of the decennial census. Data on roads spending and road stock in miles were retrieved from the Michigan Department of Transportation, Financial Services Division and the MDOT Library. These departments provided MDOT Report Series No. 139 & 162. Specifically, data by city and village for the total receipts of the Michigan Transportation Fund and locally raised revenues, and local road stock were retrieved and integrated with other data relevant for the analysis. Data processing and integration were performed using a MS Excel 2003 spreadsheet and ArcMapTM version 9.1. 105 301 1‘0 The description and presentation of these information involved mapping using existing shapefiles obtained from the official website of the Michigan Geographic Data Library, Center for Geographic Information or CGI (http://wwwmcgi.state.mi.us/mgdl/, 2009). The Database The final database contained the following fields: Name of municipality (NAME), percent population density change (%_DENSCH), percent change in non-white concentration (%_NWLQCH), per person state allocated local road revenue from Michigan Transportation Funds (MTFPP), per person locally-raised revenue (LOCALPP), proportion of white homeowners (%_WHOME), percent non-white (%_NONW), household median income (MEDINC), percent of non-whites, 25 years old and over with at least four years college education (%_CONW), local road density (LOCRDENS), and the distance measure between the Detroit CBD and each of community in the study region (DISTDET). Since some explanatory variables use monetary value as a measure, dollar values for these variables are converted into 2008 dollar amount to account for inflation using conversion factors on consumer price index (CPI) that are listed in the Bureau of Labor Statistics website. The conversion of dollar values into current values enhances comparability when analyzing objects and entities that changes values over time such as money. A summary of the variables used in the analysis and their data sources is listed in Table 5.2. 106 Table 5.2. Variables and their Sources Variable Description of variable Source %_DEN SCH Percent change in population Computed by the author densityl980-l 990 based on data from the Census CD 1980-1990 GeoLytics, Incorporated %_NWLQCH Percent change in non-white Computed by the author concentration, 1980-1990 using population count from Census CD 1980 and 1990 MTFPP77 Per capital state road revenue, in S, Michigan Dept of 1977 Transportation, Report #162 and #139 LOCALPP77 Per capita locally-raised road Michigan Dept of revenue, in $, 1977 Transportation, Report #162 LOCRDENS77 Local road density=total local roads Computed by the author in miles/area, 1977 using data from MDOT report #162 FAEDINcso Household median income, 1980 National Historical GIS, Population Center, U of Minnesota %_CONWSO Percent of non-whites, 25+ years 4 years college education, 1980 Census CD 1980-1990 GeoLytics, Incorporated I %_WHOME80 Percent white homeowners/ Percent white population, 1980 Census CD 1980-1990 GeoLflics, Incorporated %_NONWSO Percent non-whites (Blacks, Native Computed by the author Americans, Aleut, Alaskan, Asians based on data fi'om Census and Pacific Islander, Others), 1980 CD 1980-1990 GeoLytics, Incorporated DIS TDET Distance from Detroit CBD, in Computed by the author miles using Hawth’s Tools ArcGIS Extension 107 are g e115 m 100. Re; 001 Ob; be‘ Empirical Model Estimation In quantitative analysis, correlations and regression are statistical techniques that are generally adopted to determine whether a relationship between two or more processes exists. Bivariate correlation statistics measure the degree of association between two variables, while regression analysis takes one step further by exploring the degree of fit of this relationship (Kachigan, 1986). Multivariate regression analysis is used in determining the relationship between local roads and decentralization process in the context of the Detroit Metropolitan region. Regression is a statistical technique that is most often adopted in modeling spatial and non spatial processes and is used in both simple and multivariate estimation. The overall objectives of regression analysis are: l) to determine whether or not a relationship exists between two variables (in simple/univariate regression); 2) to describe the nature of the relationship, should one exist, in the form of mathematical equation; 3) to assess the degree of accuracy of description or prediction achieved by the regression equation, and 4) in the case of multiple regression, to assess the relative importance of the various Predictor variables in their contribution to variation in the criterion or dependent variable (Kachi gan,1986; p. 239). The Ordinary Least Squares technique is used in the estimation of the empirical model 0f the causal relationship between local roads and the decentralization of people b 3’ race Within the context of the Detroit Metropolitan region. The dependent variable in the model is a rate of change between two time periods (1980 and 1990). The i I-ldel’endent variables are lagged variables or the initial condition and are therefore Stlmated coefficrents of the extent that the rnrtral condition affects the trajectory or 108 future direction of growth and subsequently patterns of decentralization. The use of lagged independent variables is necessary given that a cross section data may not lend a straightforward interpretation of cause and effect. However, to the extent that initial condition precedes growth and decentralization outcomes, one must consider the “priorness” of the initial condition. Thus, the causal relationship between local roads spending and decentralization is better understood by recognizing the initial condition of explanatory variables and the extent by which it affects future grth and decentralization. Ordinary Least Squares The Ordinary Least Squares technique is based on the following assumptions: 1) explanatory or predictor variables are independent; 2) The expected or mean value of the residuals is zero; 3) residuals are homoskedastic and independent from one another; and 4) residuals are normally distributed (Bailey & Gattrell, 1995). Essentially, OLS assumes a linear relationship between the predictor and criterion variables and seeks to estimate the parameter/s that provides the best fitting linear relationship. The OLS equation takes the fom1: It Y=a+ Zflixi+£;where (5.4) 3:] Y is the dependent or criterion variable, a is the Y intercept (the value of Y when x = O), B i is the coefficients of the independent variables, X. is independent or predictor V ' - arrables, and s 13 the error term. 109 To understand how each variable adequately explains the decentralization process in metropolitan areas, the dissertation adopts a stepwise regression via forward selection approach. This approach helps “single out” the simplest model that describes the decentralization process or other processes of interest. Essentially, the approach enables a process of identifying significant independent variables in the model, one variable at a time (Kachigan, 1986). Variable Transformation Prior to modeling, univariate tests for normality are performed on the model variables to account for normality assumption of the Ordinary Least Squares (OLS). The histograms for all variables in the model are plotted and presented in Appendix B. Natural log transformation was performed for a few variables but since these did not yield meaningful coefficients particularly since the dependent variable is measured in proportion (Bailey & Gatrell, 1995; p. 276-277), a re-estimation without the log transformation was made and results were retained for further analysis. Assumption of independence of errors is further tested by employing the Moran’s I Statisti c on the model residuals (Moran, 1950). These tests have implications for the goodness of fit of the model (Bailey & Gattrell, 1995). Moran’s I is a weighted correlation coefficient that identifies deviations from Spatial randomness. If a pattern of distribution of the values of variable or certain spatial process 00 curs, the process is said to indicate spatial autocorrelation (Anselin, 2005). A Spatially autocorrelated process indicates a biased and imprecise OLS estimator. It is b ‘ . . 1 ased beczause events that are clustered or concentrated Will have a greater impact on the 110 estimate (Kachigan, 1986). With clustering of events, fewer number of independent observations than assumed affects the precision of the estimate. Moran’s I takes the form: "2 chj(yc ‘TXJ’,’ —;) I- c=lj=l n _ 2 ;where, (5,5) 2(yc —y) X Z we] C=1 c¢j n is the number of observations or communities, yc is the value of a variable at location c, yj is the value of a variable at location j, y is the mean value ofvariable y, wcj- is the weight coefficient for the lag separation between c and 1' based on a proximity weight matrix W. Moran’s 1 takes the value of -l.0 to 1.0. Values with positive coefficients suggest that the surrounding values of an observation i at a specific location c increase as the value of i increases. Conversely, negative coefficients suggest that the surrounding values 0f observation i at location c decrease as value of i increases. A zero coefficient suggests that spatial dependence is not observed in the process under study. This diagnostics test on mod 61 residuals provides information on the fit of the OLS model and allows al temati ve modeling technique to be explored. Spatial Lag Model Since area data tends to exhibit violations in assumption of independence in errors %d ObserVation (Anselin, 2005), the spatial lag model as an alternative to the standard LS regrtitssron technique 18 used. The altematrve model 13 chosen to capture second 111 order effects or the spatial autocorrelation of model residuals that a standard OLS regression do not account for, thereby making inflated and biased estimates (Bailey & Gatrell, 1995; p. 287). The spatial lag form introduces a spatial autocorrelation coefficient rho, p, which indicates a diffusion or “spillover” effect of the process. It captures the influence of neighboring values of dependent variables on the dependent variable or process of interest. To operationalize a spatial lag model, a spatial weight matrix W is developed using alternative proximity measurements. A k nearest neighbor proximity matrix is adopted in this research and the model is estimated by maximum likelihood estimation (Anselin, 2005). From Bailey & Gatrell (1995, p. 288), the spatial lag k model is: Y = Xfl+pWY+ a; where, (5.6) Y, the random variable of the process of interest, is a function of a trend component X )3,- a second order component pWY, and s is vector of independent random errors. And, 13 is a vector of parameters to be estimated, p is a spatial autoregressive coefficient indicating the influence of nearby values of Y, W is the proximity matrix. For the empirical model estimation of the relationship between local roads and patterns of decentralization, the R statistical software (R, 2004) and GeoDA (Anselin, 2 005) are used. The R analysis used three libraries including: foreign (DebRoy et a1, 4/ 1 90005), maptools (Bivand et al, 3/4/2005), and spdep (Bivand et a1, 4/19/2005). The S tatistical Package for Social Science (SPSS) version 17 is also used for initial data 112 processing and management. Data integration and mapping were performed using ArcGIS 9.1. Summary of Data and Estimation Procedure The empirical estimation of the relationship uses the Ordinary Least Squares (OLS) regression technique. Subsequently, a stepwise regression is performed to address possible multicollinearity issue among independent variables and simplify the model. Further, Moran’s 1 statistic is determined to account for the possible violation of independence in the model residuals. Finally, an alternative model, spatial lag, is specified to account for the structure or second order effects of the process. The next chapter presents the descriptive statistics for the study area. It also presents the results of the statistical model estimation of the relationship between local roads and the differential levels of decentralization of people by race in the Detroit ‘Metropolitan region. A discussion of results of model estimation, and a brief summary of the findings are also included. 113 CHAPTER SIX: RESULTS AND DISCUSSION To reiterate, the objective of this study is to understand the relationship between local roads spending and the decentralization of people in metropolitan areas. Also, the specific goals of the study, listed in Chapter 4, are to 1) develop the conceptual model of the causal relationship between local roads and decentralization using three measures of decentralization; 2) describe the pattern of population density change and the concentration or representation of non-white population; 3) describe the road spending variables and their distribution; and 4) test the empirical model using data from a specific case study of the Detroit Metropolitan region. In this dissertation research, decentralization is understood using three specific indicators: 1) percent density change of the general or total population; 2) percent change in non-white concentration or representation; and 3) percent change in non-white population density of each community across the study region. The effects of local roads spending on decentralization are estimated while accounting for other proposed predictor variabl es: income and education, the demographic composition or percent non-white, the Proportion of white homeowners to the proportion of white population, and distance between the Detroit CBD. This chapter presents the empirical estimates, statistical results of the hypotheses tests, and discussions of findings. The first section of the chapter presents the descriptive Statistics - This is followed by the analytical results of the hypotheses testing. A discussion 0 f key results ends the chapter. 114 Descriptive Characteristics of the Study Region The Detroit Metropolitan region comprises a total of 131 townships, villages, and cities, with two communities straddled between two counties (Southeast Michigan Council of Governments, 2002). Eighty eight (88) of these communities, all of which are incorporated cities and villages, are identified as study communities. These communities vary in land area, and land use intensities (See Figure 1.1, Chapter 1). The average population in a given community was 38,156 in 1980 and 35,306 in 1990. The land area across the study communities is on average, 9.31 square miles and ranges from 0.25 to l 42.92 square miles. Population Density The population density across the study region ranged from 131 to 10,172 persons per square mile in 1980, and 179 to 7,422 in 1990. The population density in a given comm unity in the region averaged 3,528 in 1980 and 3,047 in 1990. The decrease in the average population density in the study region between 1980 and 1990 reflects population redistri bution as Opposed to shifts in land area since it is assumed that land area for each Community remained static between 1980 and 1990. Indeed, unlike in the earlier decades, very few city or village incorporations took place between 19803 and 19903 in the region (SEMCOG, 2002). Within the study region, only three city incorporations are noted in the 19803 including Lake Angelus (1984), ALIbum H ills (1983), and Rochester Hills (1984). Thus, the average percent change in 130plllaliiorl density across the study region, which is 23 percent, reflects the percent I)qulafion growth in a given community. It shows the dynamic nature of the growth 115 process such that while a community may have increased in population density by as high . as 454 percent between 1980 and 1990, some others decreased by 95.31 percent. An examination of the spatial distribution of the changes in percent population density across the study region reveals the location of communities that experienced a significant change in population density. Figure 6.1 shows that the central city (Detroit), communities immediately surrounding the central city, as well as Pontiac experienced a stark decline in population density. Many outlying and small communities in the region, on the other hand, experienced an increase in population density, thus, providing evidence of the decentralization process occurring in the region during the study period. As it shows, communities north of the city of Detroit, a few in the northwest side and a small cluster in the south of the city experienced population density increase between the 1980 and 1990 by as much as 454%. On the other hand, the city of Detroit and many of the surrounding communities declined by as low as 95.31 percent while a couple of communities indicated no change between 1980 and 1990. 116 I: .9531 - 68.48 - -68.47 - -27.03 - -27.02 - 5.22 - 5.23 - 40.97 - 40.98 - 454.64 I: Township 0 2.5 5 10 Miles 1—1—1—1—1—1—1—1-1 Figure 6.1. Percent Population Density Change, Detroit MSA, 1980-1990 117 A more interesting snapshot of population redistribution in the region can be gleaned from Figure 6.2. Figure 6.2 shows the combined population for each group of communities according to their distance from the central city of Detroit. The travel time estimates are adopted from the Southeast Michigan Council of Governments (SEMCOG, 2002), which provided an estimated travel time between Detroit CBD and individual communities in the region during peak or rush hours. Communities located within 1 to 15 minutes from the central business district of the city of Detroit decreased in population since the 19703. Communities located within 16 to30 minutes away fi'om the central business district of Detroit, or the inner ring suburbs, also experienced a similar trend though some slight increase in the population is observed since the late 19803. The outlying communities, those located beyond 30 minutes away from the central business district of Detroit experienced increases in population. What is important to note is that communities that are located within 30 to 45 minutes away from the city of Detroit were fast growing relative to other communities in the region. How do racial composition, socio-economic characteristics, and local roads stock and spending reflect the pattern of population distribution in the region? The next section provides descriptive statistics of each of the factors proposed to explain the pattern of decentralization in metropolitan areas. The proposed factors are derived from a review of segregation and residential patterns literature presented in Chapter Two. 118 03 r» I\ N N [s 1 1 1 or 00 N 60 . ‘- 93 93 g 82 g N 60+ Travel time from CBD Year " ‘- N (minutes) Figure 6.2. Population Change by Travel Time: 1972-2002 Source: Computed by the author using population estimates from the US Census Bureau, Census of Governments files, 1972-2002 119 Patterns of Decentralization of Non-whites An interesting aspect of the variation in community level population density is its possible connection to the spatial distribution of the non-white population in the region. The pairwise correlation statistics (Appendix C) indicates that these two processes are positively associated at a statistically significant level of less than 0.05 though the strength of this relationship is not strong (Pearson r = 0.232, p < 0.05). The non-white population, which comprises the total population count of blacks or Afiican Americans, Hispanics, Native Americans, Eskimo, Aleut, Asians and Pacific Islander, and others, are situated unevenly across the study region. Figure 6.3 and 6.4 show that while there is a representation of the non-white population across the different communities of the study region, they are mainly overrepresented or highly concentrated in a few communities. Communities with location quotient greater than 1.0 indicate a relative concentration of non-whites as can be gleaned from Figure 6.3 and 6.4. These maps identify specific communities that have highest relative concentration of the non- white population in the region and reveal the link between concentration of non-whites and community population 1033. Figure 6.3 shows that in 1980, cities such as Highland Park, Detroit, Plymouth, Inkster, Ecorse, Pontiac, New Haven, River Rouge, Utica, South Lyon, and Wixom were home to a large proportion of non-whites (LQ > 1.0) relative to the Detroit Metropolitan region as the reference area. Seven of these ten cities have the highest concentration of non-white population including Highland Park (LQ=3.52), Detroit (LQ=2.63), Plymouth (LQ=2.52), 1nkster(LQ=2.45), Ecorse (LQ=1.64), Pontiac (LQ=1.55), New Haven (LQ=1.40), and River Rouge (LQ=1.37). 120 A similar distribution of non-whites’ relative concentration in the 1990 can be gleaned from Figure 6.4. Communities that indicated a high concentration of non-whites in 1980 remained highly concentrated in 1990. Oak Park became highly concentrated by 1990 as well. Altogether, Highland Park, Detroit, New Haven, Inkster, Pontiac, Ecorse, Oak Park, River Rouge and Southfield had high concentration of non-whites among the study communities in the region. Except for Southfield, these cities had a Location Quotient that is greater than 1.00 (LQ > 1.0). While Figures 6.3 and 6.4 provide a static description of the presence and concentration of the non-white population in the study region, a map of the percent change in the concentration of the non-white population between 1980 and 1990 offers another dimension for analyzing the dynamic character of the distribution of people by race within a decade. Figure 6.5 shows that although many communities in the study region had a considerable presence of non-whites, non-whites are not overrepresented in these communities relative to the region as a whole. These communities had location quotients less than 1.0 or a LQ of 0.01 to 0.99. However, it can be argued that these communities may have increasingly become the “destination” communities for non- whites. 121 [:l 0.00 - 0.01—0.41 - 0.42 - 0.99 - 1-00 - 1.01 _ 3.52 1:] Townshlp 0 2.5 5 10 Miles l—l—l—I—l—I—l—l—l Figure 6.3. Relative Concentration of N on-whites, Detroit MSA, 1980 122 Figure 6.4. Relative Concentration of Non-whites, Detroit MSA, 1990 123 Specifically, communities in the periphery or the first ring suburban areas immediately surrounding the city of Detroit, and some distant villages toward the north experienced gains in non-white residents by over 200 percent within a decade. The top gainers or retainers of non-white population between 1980 and 1990 include Farmington, Garden, Warren, Royal Oak, Melvindale, Farmington Hills, Ortonville, Novi, Dearbom, and Sterling Heights with percentage change that ranges from 551 to 1,235 percent (Figure 6.5). On the other hand, five communities were least gainers or retainers of non- white population including Highland Park, River Rouge, Gibraltar, Hamtramck, Fraser, Detroit, and Pontiac. These seven communities indicated a gain of non-white population that ranges from 1 to 18 percent. However, the gains in these seven communities and the overall redistribution and concentration of non-white population need be interpreted with caution. It is possible that the increase in non-white population could be due to “white flight” and not necessarily an influx of non-whites to these communities. It is also possible that both processes, whites fleeing and blacks moving in, to be simultaneously occurring. Nonetheless, the shifts in rate of concentration reveal the degree of change in the socio-spatial separation between whites and non~whites. 124 I MAC OMB OAKLAND I P w ‘ I I“ "' . l... N "I l A I 'l‘. 0 1‘36 1:] —98.32 - -31.24 - -31.23 - 69.63 - 69.64 - 214.05 - 214.06 - 551.46 - 551.47 - 1235.18 [:1 Township 1 r 0 2.5 5 10 Miles l-+—+—l--|—l-H—| I“figure 6.5. Percent Change in the Relative Concentration of Non-whites, Detroit MSA, 1980-1990 125 Socioeconomic Characteristics and Homeownership As described above, the population redistribution in the Detroit Metropolitan region fits well with the process of decentralization. The Detroit Metropolitan region experienced significant population redistribution and a distinct racial composition. Measures of socioeconomic characteristics and homeownership reflect the population and racial fabric. The household median income, educational attainment, and homeownership reveal the disparity across the study communities. The average household median income across the study communities was $61,923 . 79 in 1980 and $68,170.69 in 1990. The income disparity across the region is clearly revealed in the range, which is $149,797.38 in 1980 and $228,520 in 1990. Figure 6.6 illustrates a scatter plot of the distribution of communities by household median income with respect to distance of each study community from the Detroit CBD. The plot generally indicates a decreasing trend of household median income with communities that are located farther fiom the CBD. However, the plot also indicates that most of the economically endowed communities are located within 10 and 25 miles of the Detroit CBD. 126 200,000 - A 180,000 - o 3’? 160,000- l40,000 ‘ 0 120,000 ‘ O . [100,000 - 0° 0 80,000- 00 ° o°°0 O O 991W ’ o 0 40,000- 0 o O % 0% 0° 80 0 Household Medran Income 20,000 - ° 0 u . u r . 0 10 20 30 4O 50 Distance from Detroit CBD (miles) Figure 6.6. Household Median Income by Distance from Detroit CBD (1980) The disparity across the study communities is not just revealed by household median income but by levels of educational attainment and homeownership as well. On average, there is a lower proportion of non-whites with college education across the study communities. On average, a given community has less than 1 percent or 0.55 percent of non-white population who had at least 25 years old and completed 4 years of college education in 19803. A majority of educated residents in a given community were still mostly whites. Similarly, the proportion of white homeowners to the proportion of white population in a given community is also very high. On average, almost all of white residents in a given community in 1980 owned their home (average estimated homeownership index = 0.97). In 1990, this proportion was even higher, 1.03, indicating that some communities have had over representation of whites who own a home relative to the community’s white population. 127 The high representation of white home owners in a given community could suggest greater incidence of discrimination in housing. In the Detroit Metropolitan region, this white homeownership index ranges from 0.67 to 1.86 in 1980 and 0.95 to 1.54 in 1990. Clearly, a high proportion of whites own their home relative to their non- white counterparts. Local Roads Spending and Local Roads Stock The variation in population size, land use intensity, and socio-economic and demographic characteristics in the study region reflects variation in the amount of funds that each community receives for local roads development and maintenance from the state government and other sources including locally-raised or contributions coming from the local government. Hence, the local roads stock and spending reveals such variation. The Local Road Revenue, State Allocated The Michigan Transportation Fund allocation for local roads development remains the primary source of revenue for local roads development and maintenance in the state of Michigan. For cities and villages, the average per person allocation amounted to $59.24 in 1977. The dollar amount that each community receives reflects the community’s population size and road mileage in a given time period. The state allocation across these communities ranges from $37.42 to $138.01 and $5.03 to $89.70 per person in 1977 and 1987, respectively. The decline in average allocation from 1977 to 1987 is noteworthy. It suggests many factors affecting the allocation of revenues 128 including population shifts as well as the total amount of revenue that is generated by the state as a whole prior distribution (Welke et al., 2000). Patterns of M TF Allocation in the Detroit Metropolitan Area All cities and villages in the Detroit MSA have consistently received the state allocated local roads revenue through the Michigan Transportation Fund (MTF) of Public Act 51 of 1951. However, disparity in allocation has been observed as can be gleaned from Figure 6.7. This figure shows that the total share of the city of Detroit has declined over time. The proportion of the MTF allocation for the city of Detroit in relation to total allocation of the metropolitan region ranged from 56% in 1953 to 37 % in 2002, indicating a decreasing trend of the city’s share over time. This is not surprising, considering the pattern of population distribution in the region described above. Figure 6.8 and 6.9 present spatial distribution of state-allocated roads funds across the study communities in 1977 and 1987. The values are expressed in dollars per person and show the variation of allocation across the communities. These two maps show a slightly different distribution of local road funds. In particular, some communities in Oakland and Macomb counties have had relatively higher per capita state-allocated local road funds than communities in Wayne county in 1977 (Figure 6.8). This pattern changed by 1987 (Figure 6.9) when all counties including Wayne, Oakland, and Macomb have had some communities that experienced a relatively higher per capita roads allocation. The reduction in per capita allocation from 1977 to 1987 is noteworthy. The change in per capita allocation for communities fiom a maximum of $138.01 in 1977 to 129 $89.97 is maybe explained by several factors including a reduction in overall MTF revenue which affects local road allocation. The Locally-raised Road Revenue, Local Contributions To reiterate, the locally-raised road revenue presents another major source of funding for local roads development and maintenance for Michigan communities. Locally-raised road revenue generation for many communities has declined. Specifically between 1977 and 1987, communities experienced an average decrease in their ability to generate and spend for their local roads development and maintenance, which is similar to the pattern of state spending on local roads. The trend indicates that for local communities, their capacity to fund local roads development tended to decline over time as well. The average per person road revenue that a given community generated amounted to $49.40 and $16.41 in 1977 and 1987, respectively (Table 6.1). The locally-raised road dollars ranged fiom $0 to $355.00 in 1977 and $0 to 290.53 in 1987. The zero value indicates that some communities either did not report any local contributions or these communities may have fully relied from other sources for development and maintenance of their road stock. Figure 6.10 and 6.11 present variation of per capita locally-raised road revenues that individual communities generated for 1977 and 1987. These maps show the changes between the specified time periods described above. In terms of local roads stock, the local road stock across the study communities did not significantly change in a decade. Between 1977 and 1987, there was an average increase of 1.97 miles per square mile across the study communities. The average local 130 road density was 21.29 in 1977 and 23.21 in 1987. Figure 6.12 and 6.13 show the individual local road density by year and the slight change that can be gleaned from them. They show that a slight increase in road density in 1987 in some communities in Oakland and Macomb counties is apparent. 100 090 050 - 070 060 7 0.50 : DetroitIMSA 040 030 7 020 - 010 - 000 . - . - - : - 1950 1960 1970 1980 1990 2000 2010 Year Figure 6.7. MTF Allocation: Proportion of the City of Detroit to the Total Metropolitan Region, 1952-2002 Source: Computed by the author based on MDOT Reports #139 131 - 0.01- 5534 - 55.95- 67.65 - 67.66- 96.81 - 96.82- 138.01 I: Township 0 2.5 5 10 Miles |-—1—+—1+1—1—1—1 Figure 6.8. Per Person State-allocated Local Roads Revenue (5), Detroit MSA, 1977 I32 - 0.01- 47.58 - 4759— 55.25 - 55.26- 69.58 - 69.59 - 89.97 C] Township 0 2.5 5 10 Miles l—H—l—l—l—l—l—I Figure 6.9. Per Person State-allocated Local Roads Revenue (S), Detroit MSA, 1987 133 - 0.01 - 59.00 - 59.01 — 103.00 - 103.01 - 188.00 - 188.01 - 355.00 :1 Township 0 2.5 5 10 Miles H—l—H—l—I—l—l Figure 6.10. Per Person Locally-raised Road Revenue (S), Detroit MSA, 1977 134 [:1 0.00 - 0.01 - 22.93 - 22.94 - 38.18 - 38.19 - 65.90 - 65.91 — 290.53 :1 Township 0 2.5 5 10 Miles l—i—i—H—i—i—i-l Figure 6.11. Per Person Locally-raised Road Revenue (S), Detroit MSA, 1987 135 - 4.34 - 8.20 - 8.21 - 11.64 - 11.65 - 16.14 - 16.15-21.29 l:l Township 0 2.5 5 10 Miles 1—1—1—1—1—4—1—1—1 Figure 6.12. Local Road Density, Detroit MSA, 1977 136 - 4.74 - 8.58 - 8.59 - 11.66 - 11.67- 15.77 - 15.78 -23.21 :1 Township 0 2.5 5 10 Miles 1—1—1—1—1—1—1—1—1 Figure 6.13. 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Analytical Results To determine the relationship between local roads and population decentralization, an empirical estimation of three fully specified models of three indicators of pattern of decentralization for the general and non-white population is performed via the standard Ordinary Least Squares (OLS) approach. A stepwise regression is then performed to identify a less comprehensive and underlying sub-model (if it exists) of the process. To determine the fit of the model and possible violation of the OLS assumptions, the model residuals are examined using the Moran’s I statistic. Subsequently, considering the likelihood of spatial autocorrelation of the residuals, an alternative spatial lag model specification is estimated to account for possible violation of the assumption of independence of errors in OLS and to improve the predictive power of the model. Model Estimation Two hypotheses are tested to determine the causal relationship between local roads and decentralization. The three measures of the pattern of decentralization, as dependent variables, are: 1) percent change in population density as a measure of pattern of decentralization of the general or total population; 2) percent change in relative concentration of non-white as a measure of the pattern of decentralization of non-white population; and 3) percent change in population density of non-whites as a second measure of pattern of decentralization of the non-white population. Each measure is regressed against eight proposed predictor variables. 140 Recall that from Chapter Four, the empirical model of population decentralization is developed using three theoretical perspectives of segregation and residential patterns literature — spatial assimilation, neighborhood preference, and place stratification — and were integrated into the human ecological framework of decentralization. To reiterate, the model for estimation takes the form: ADecentralization it =f(Road spending and density(,.1),-, Income(,_1)i, Education“. 1);, %Non-whites(,.1)i, Proportion of White home owners(,_1),-, Distance, 8;); where, (6.1) As explained above, there are three dependent variables used as indicators of decentralization. The road spending and road density variables include state allocated road revenue, locally-raised revenues for local roads development, and local roads density as measures of policy effects on decentralization. The income and education variables reflect financial status that measures capacity for spatial mobility. The percent non-whites measures neighborhood composition, which reflects individual or group’s preference for either homogeneous or diverse community. The proportion of white homeowners is an index of relative concentration of white homeowners in a community as proxy for housing discrimination. Finally, distance is a measure of proximity to a central business district (CBD), specifically to the city of Detroit. It reflects locational preference and impacts of spatial separation between communities and the CBD on patterns of population decentralization. The error term, 8,, is random error or remaining variability, and t-I represents previous or lagged values of variables in the model. 141 The ten year lag reflects the expected length of tenure for all homeowners across the US. That is, ten years is the median number of years between a purchase and resell of a given house (National Association of Realtors, 2008). The lagged variable in the model essentially captures the impact of previous conditions of the conceptualized predictors on the future condition of the process of interest, such as population density change as a measure of the pattern of decentralization in a given region. The model described above posits that the decentralization of people in metropolitan areas is a function of government policy on local roads development (environmental component). However, it also accounts for other proposed predictors reflecting impacts of socio-economic or financial status (population component based on ecological and spatial assimilation perspective), demographic composition (behavior component based on neighborhood preference perspective), and social exclusion or discrimination (behavior component based on spatial stratification perspective) as conceptualized predictors for the pattern of decentralization of people. For the rest of the chapter, Equation 6.2 is used to explain decentralization using the three indicators presented above. See Table 5.1 for a summary of variable description and their sources. ADecentralization1930_1990i = ’60 + p(°/o __ DENSCHi) + fl] MTFPP 77" + flzLOCALPP 77; + fi3L0CRDENS 77 ,. + ,64MEDINC80; + fl5°/o_C0NW 80,- + o6%_ NONW 80,- + ,67%_WH0ME 80,- + ,BsblSTDETi + a, (6.2) The following section provides results of the empirical estimation of each of the three models of decentralization. For each model, a full and reduced (by stepwise 142 regression) form are estimated using the standard Ordinary Least Squares and Spatial regression techniques. Discussions of results of each model are presented in a separate section of the chapter. Pattern of Decentralization: Total Population Decentralization of Total Population: Ordinary Least Squares Regression Results, Full Specification Fully specified and reduced model were estimated to determine the relationship between local roads and pattern of decentralization of the total population while controlling for other proposed predictor variables. The model intends to capture what explains decentralization in general, which is the pattern of decentralization of combined whites and non-whites population groups. Results of a fully specified model (percent change in population density) estimation using the Ordinary Least Squares (OLS) approach indicates an adjusted R square value of 0.40. Hence, 40 percent of the variation on the percent change in population density is explained by eight (8) conceptualized predictors. The Moran’s 1 statistic is 0.01 and is not significant, which indicates that spatial autocorrelation of the model residual is not an issue in the model. A residual map is presented in Figure 6.14. 143 - 402.54 - -S9.65 - .59.“ - -9.12 - -9.12 - -0.01 - -0.02 - nus - 118.24 - 360.53 C] Township 0 2.5 5 10 Miles I-H—l—i—l—i—l—I Figure 6.14. Percent Change in Population Density Model Residuals 144 Four of the eight conceptualized predictor variables in the model are statistically significant. The estimated coefficient of government policy effects or state—allocated local road spending on decentralization is 0.86 and is statistically significant at less than 5 percent level (p< 0.05). The coefficient of socio-economic effects or household median income is 0.001 and is statistically significant at less than 1 percent level (p<0.01). The coefficient for demographic composition, which is percent non-white is -0.97 and is statistically significant at less than 5 percent level (p< 0.05). The coefficient for the spatial or locational attributes and spatial separation measure, which is distance from the central business district is 4.51 and is statistically significant at less than 0.] percent (p<0.001). The coefficients indicate that communities with higher per capita state-allocated road spending, household median income, and with increasing distance from the CBD experienced an increase in population density and this increase reflects a pattern of decentralization of the total population. However, the stronger presence of non-whites in a given community has a negative effect on the rate of change of population density. It appears that a stronger presence of non-white residents in a given community induces repulsion fi'om rather than attraction to the community. Decentralization of Total Population: Spatial Regression Results, Full Specification Data tends to result in a violation of normality, constant variance, and independence of errors (Bailey & Gatrell, 1995; Kachigan, 1986). For area data, data that are aggregated into different area] units such as census zones, municipalities, voting districts, the OLS assumptions do not hold well and are often violated. This is particularly 145 so since “areal data give rise to many spatial relationships” (Bailey & Gatrell, 1995; p. 20) and these spatial relationships can take in many forms with corresponding relevant measurement or description. For example, if one wants to assess the degree of segregation between and among particular population groups, there are several ways for describing their spatial relationship. Clustering, exposure, isolation, and concentration are possible measures that each can be described in a number of ways (Massey & Denton, 1985). If the interest is spatial distribution of shoppers across a region, travel cost and travel time maybe used to describe the spatial relationship. Some spatial relationships are described in days traveled by feet in societies or communities that lack modern transportation. Hence, different spatial relationships can be gleaned from aerial data and relevant measures can be used to describe these relationships. Due to an inherent presence of spatial relationship in areal data, it is highly likely that spatial autocorrelation in the model residual will be observed. Hence, a spatial lag model is estimated to capture spatial autocorrelation of errors, and improve prediction. For a spatial lag model, a proximity matrix using 3 and 5 nearest neighbors is developed for this study. Results of the spatial lag model estimation confirmed the notion of a presence of spatial autocorrelation in the model residuals. The spatial autocorrelation coefficient rho (p) is high and statistically significant at less than 0.1% (p = 0.43; p<0.001) for the spatial lag model using the 3 nearest neighbors, and p = 0.38 (p<0.001 ) for the 5 nearest neighbors. In addition, the effect of the presence of non-white population with college education is significant. The coefficients are -6.32 (p<0.05) using the 3 nearest neighbors, 146 and -5.13 (p<0.10) using the 5 nearest neighbors proximity matrix. Hence, an inverse relationship seems to exist between the presence of non-whites and the pattern of decentralization of the general or total population. Results from the spatial lag model estimation confirmed a presence of the spatial autocorrelation in the model residuals. These also suggest that the spatial lag model performed better than the OLS as can be observed from the tests for multivariate normality including the log likelihood, Schwarz and AIC criteria (Anselin, 2005; p. 175). Both the spatial lag models using 3 and 5 nearest neighbors have a higher log likelihood values (3nn, -481.583; 5nn, -483.94) than that of the OLS (-487.14) estimation. The AIC (3nn, 983.06; 5nn, 987.89) and Schwarz (3nn, 1007.83; 5nn, 1012.66) criteria for spatial lag models are also slightly lower than the OLS values (AIC=992.28, Schwarz=1014.58). Comparatively speaking, the spatial lag model performed better than the OLS model estimates and is able to capture the secondary effects of the process. Except for the effect of the college educated non-white residents and the presence of non-white population in a given community, the coefficients of the significant predictors (state-allocated road spending, household median income, percent non-whites, and distance from the central business district) are consistently higher and statistically significant. Table 6.2 summarizes these results. These results show positive effects of state-allocated local road spending on decentralization. As the coefficients show, local road spending facilitates population growth in suburban communities and this growth contributes to the decentralization in metropolitan areas. 147 Save a 48.0%N t... .8? a I. gov m .. :32 858$an taco Ian-v.0 22 * *Nfio Ed 2366px ~ MSW-52 8.22 Ea z: 3.82 $.32 8:25 53% an? gas a. as ES? 8er: MS $.23 ”.23 8.93 380 02 MS mg 88% a one 93 03:3 m .a< So as as as 23% m Imam m: I... 5. 28m m: I... 5. 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The fully specified model indicates that 24 percent of the variation is explained by the eight proposed predictor variables. Presence of autocorrelation in the model residuals is examined using the Moran’s 1 statistic coefficient. The coefficient is 0.009 and is not statistically significant (1 = 0.009, p = 0.67). A spatial lag model is further estimated but results indicate that the lag model did not improve the prediction of the OLS model. The spatial autocorrelation coefficient p is positive but not statistically significant (p = 0.06). Therefore, the model estimate from OLS is retained for analysis. Overall, results indicate that only the locational or geographical factor, distance from the central business district is statistically significant at less than 0.1 percent. The estimate indicates that for every mile that a community is located farther away fi'om the Detroit CBD, a corresponding decline of 4.8 percent in the non-white population density is expected. Similarly, the model indicates that a greater presence of non-whites also affect the overall non-White’s decentralization pattern. Thus, the strength of the locational or geographical factor and demographic composition are important considerations in understanding the pattern decentralization non-whites. Table 6.6 summarizes the results of the full OLS model estimation of the percent change of non-white density and the proposed predictor variables. 159 Evan .53!N I... .8? a .1. gov a .. ”:32 85055 :.o- 80 a mod mod mam-528% d @552 added" 0.003 0.33 0.33 :otoEU ~33ng H0.va- 00:043- mmdwv- $.me 085:3: we: 8.33 3...“? 2423 omxcdd 02 hmé 50+ oamufim u go Rd 05% m .6... Ed de de de 0.833 M .3156- oo; 3.3%.? *Inwd- do; 31%.? 3:8 E :obuQ an 8:8me 84mm 2.0m mwam mm.mm 3.0m mw.mm dwfi mEmSFsooEon BBB X. 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NE. SN. 3%. a s a» $323.18: ox. _ «8.- v8.- .mmm. me. ”2.. NS; t 8328 .x. E mm an an an mm mm 2 23— 2:85 Se. Sm. :o. o2. mm». a 562: 228.8: _ 25. So.- 29. at. «8.- t 802592 GO 2- ns an on on 2 m6 moo. coo. So. Non. Q 3 can 38.. .82 .80..- _ :N _ n- red..- :emm.- 35. t 555963 E 3- wwo. an . my. W m 02.26: .32 woman _ 3m. MM ”- van. a #:80— :8qu com : . Ema-.53 5 on as as 2 m 2:55.. 25. 3%. Q memo. 88m .538 com _ :34. :8. t Ema-:2 5 mm mm Z owe—£0 m8. Q bicep coca—smog .X. _ mm. L Ema-51.x. 5 mm Z E3830 cosmos Q 833-8: E omega .X. _ t 5332...; 5 8: € 5 5 3v 5 as 5 € 3 032:9 nae-5:239 83333 U hazwmfivt 205 :3 VA 1. .85 Va .. ”.96— oogommcwmm 2 3205000 cows—8.50 new-80m S a «w 3 2 E M: 2 8o. 2 2 a8 5. 2.. ms. to. So. 2 _. 8o. 3 o««. a :28 5% 8:55 _ m8; «0 _. R _ .- m2.- ..m«c.- a _. ..S«. :53. «8.- t 5955 8: a «a 2 3 E 3 an 3 a z - 8o. So. «3. «.3. am. a G. o _ o. 25. a amtmwmrmcnflxfi” _ :89- SN. «.8.- So.. $o.- EV.- .EN,. :08.- t o «w «a «w M: R 8a. «m «a 2 mafia N8. cm. a». new. 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