THESIS mama: This is to certify that the thesis entitled A COMPARATIVE STUDY OF BEHIND-THE-NHEEL SKID CONTROL , BY DRIVERS WITH AND WITHOUT PARAPLEGIA presented by Thomas A. Titzkowski has been accepted towards fulfillment of the requirements for Ph.D. Secondary Education degree in . and Curr1culum Major professor Date Julx 241 1981 0-7639 MSU LIBRARIES -—;—_ RETURNING MATERIALS: Place in book drop to remove this checkout from your record. FINES will be charged if book is returned after the date stamped below. S A COMPARATIVE STUDY OF BEHIND-THE-WHEEL SKID CONTROL BY DRIVERS WITH AND WITHOUT PARAPLEGIA By Thomas A. Titzkowski A DISSERTATION Submitted to Michigan State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Secondary Education and Curriculum l981 i / 1/ (If? / ABSTRACT A COMPARATIVE STUDY OF BEHIND-THE-WHEEL SKID CONTROL BY DRIVERS WITH AND WITHOUT PARAPLEGIA By Thomas A. Titzkowski The evaluation of the extent of psychomotor skills possessed by drivers with specifically diagnosed physical disabilities in a critical driving situation has not been determined. With driver education pro- grams being increasingly offered to special driver populations, it is necessary to determine parameters and constraints of critical perform- ance tasks between drivers with and without physical disabilities. Drivers with paraplegia and able-bodied drivers were evaluated on the ability to perform a rear wheel skid control task. Fourteen able-bodied drivers were matched on years driving experience with l4 drivers with complete spinal cord injuries (T4-T12). The data from l3 matched subjects consisted of (l) uncontrolled or (2) controlled evaluations for l6 separate rear wheel skid control trials performed on a skid pan facility. Data were also collected on the initial direction of the skid. The study employed t-tests and a post hoc between-within ANOVA. The major findings of the investigation indicated (l) a sig- nificant performance difference between the able-bodied drivers and drivers with paraplegia in the ability to perform a rear wheel lockup Thomas A. Titzkowski skid control task; (2) the paraplegic group learned the task at a significantly slower rate than the able-bodied group; and (3) no significant difference was found in either the number or the direc— tion of uncontrolled skids for all drivers. Copyright by THOMAS A. TITZKONSKI l98l To my father, whose love, pride, and respect for his children and family have always encouraged my development. ii ACKNOWLEDGMENTS I would like to acknowledge Dr. Robert E. Gustafson, chair- person, for his professional guidance and precise review given to all stages of this study and my doctoral program. In addition, I would like to acknowledge members of my doctoral and dissertation committee, Dr. James E. Keller, Dr. Perrin E. Parkhurst, and Dr. John E. Schlick, for their contributions and assistance. I would like to acknowledge the extraordinary support given by Dr. Fredrick C. Hoffmeister, Dr. Joseph J. Pease, and Dr. Jerome Witherill through the Department of Safety Education at the University of Wisconsin-Whitewater. It is a special thanks that I give to I-Ning Huang, for his encouragement as a teacher, his statistical consultation as a researcher, and his warmth as a friend. It is with the kindest thoughts of gratitude that I acknowl- edge BeverlyJ. Palmer, who shared her insights and concerns for per- sons with physical disabilities and who was always available to answer questions and provide guidance on the rehabilitation process for per- sons with physical disabilities. And finally I thank the two special persons in my life, my wife Carol and daughter Ellen, who have unselfishly shared my life- style as a student through the many years of my development. I thank them for their love, understanding, and support. iii TABLE OF CONTENTS Page LIST OF TABLES ........................ vi LIST OF FIGURES ........................ vii Chapter I. THE NATURE OF THE PROBLEM ............... I Introduction .................... 1 Statement of Problem ................ 2 Purpose of the Study ................ 3 Importance ..................... 3 General Questions to Be Answered .......... 4 Methods of Procedures ................ 4 Basic Assumptions .................. 5 Definition of Terms ................. 6 Delimitations .................... 7 Limitations ..................... 8 Possible Application ................ 8 Organization of the Study .............. 8 II. SURVEY OF RELATED LITERATURE ............. 10 Special Driver Populations ............. lO Sensorimotor System and Functional Characteristics . l4 Skid Control .................... l5 Curriculum Content Components ............ 18 Summary ....................... l9 III. DESIGN OF THE STUDY .................. 21 Rationale ...................... 21 Hypotheses ..................... 25 Design ....................... 27 Sample ....................... 27 Procedures ..................... 28 Measures ...................... 31 Pilot Study ..................... 33 Equipment and Facilities .............. 33 Skid Pan Specifications ............... 35 Statistical Analysis ................ 36 Summary ....................... 38 iv Page IV. ANALYSIS OF RESULTS .................. 39 Matched Subjects .................. 39 Years Driving Experience and Performance Correlation .................... 41 Group Difference Analysis .............. 42 Skid Direction Analysis ............... 43 Acquisition Analysis ................ 44 Summary ....................... 47 V. FINDINGS, CONCLUSIONS, RECOMMENDATIONS, AND DISCUSSION ..................... 48 Summary ....................... 48 Findings ...................... 49 Conclusions ..................... 50 Recommendations ................... 51 Recommendations for Further Research ........ 51 Discussion ..................... 52 BIBLIOGRAPHY ......................... 57 APPENDICES .......................... 62 A. INTRODUCTORY LETTER TO SELECTED MEMBERS OF THE NATIONAL SPINAL CORD INJURY FOUNDATION ....... 63 B. ABLE-BODIED AND PARAPLEGIC QUESTIONNAIRE ....... 66 C. SKID CONTROL BRIEFING ................. 70 D. VEHICLE FAMILIARIZATION COURSE ............ 75 E. ABLE-BODIED AND PARAPLEGIC PERFORMANCE SHEETS ..... 78 F. SKID INDUCER ..................... Bl G. RIGHT-ANGLE HAND-CONTROL DEVICE ............ 83 H. PERFORMANCE DATA ................... 85 LIST OF TABLES Table Page l. Years Driving Experience ................ 40 2. Years Driving Experience and Number of Uncontrolled Skids ......................... 42 3. Group Difference in Number of Uncontrolled Trials . . . . 43 4. Skid Direction Analysis ................. 44 5. ANOVA for Drivers With and Without Paraplegia in Acquisition Ability .................. 45 vi LIST OF FIGURES Figure Page l. Vertebral Column .................... l6 2. Approach Directions .................. 3O 3. Skid Pan Dimensions .................. 37 4. Group and Trial Effect ................. 46 vii CHAPTER I THE NATURE OF THE PROBLEM Introduction Identification of objectives and the associated levels of criticality from an analysis of the driving task is generally agreed upon by driver education professionals to be a necessary prerequisite to learning. Task descriptions, instructional objectives, and criticality levels have been utilized in developing driver education curriculums based on the needs of the highway transportation system (26, 27). Although the needs of the highway transportation system may remain constant, the physical functional characteristics of driver populations do not. Special driver populations with mental retardation, hearing impairments, visual impairments, and various other physical disabilities are increasing within the highway trans- portation system. Every classification within the special popula- tions has distinct functional characteristics regarding physical capabilities and limitations toward learning the driving task. These physical limitations and capabilities of special populations must be given consideration when designing learning activities and experiences that provide understanding into the operation and control of a motor vehicle. Statement of Problem Since about 40 percent of all motor vehicle accidents involve skidding and the skid control task is rated as an objective with high criticality, evaluation of driver performance levels in the ability to control a skid is a primary concern (37). In addition, potential and licensed drivers from special populations with motor deficits, or extremity loss, deformation, or paralysis are estimated at over 10 million persons in the United States (29). Identifica- tion of potential performance ability for distinctively different types of disabilities has not yet been studied. This is especially important for nearly 925,000 persons with paralysis (l) who may be potential licensed drivers. Policies and guidelines for driver and traffic safety educa— tion developed at the Sixth National Conference on Safety Education (1980) emphasized that content components should be based on the relationship between physical and perceptual skills, knowledge and attitudes, physical and mental states, information processing, and safe driving behaviors (2). At present, determination of parameters and constraints of critical performance tasks (psychomotor skills) for physically disabled driver populations has not been identified. However, content components for the physically disabled driver education program (23, 33, 9) differ from driver education objectives (26, 27) without apparent justification. The exclusion of content components (classroom, simulation, range, or behind-the-wheel) with high criticality and high frequency must be partially based on evi- dence that indicates lack of functional driver skill performance rather than subjective judgments on the ability of a particular disability group to perform critical skill tasks. At present, evaluation of the extent of psychomotor skills possessed by drivers with a specific disability in a critical driving situation has not been approached. Few studies distinguish among or within neurologic, orthopedic, or mental disabilities. Purpose of the Study The central purpose of this study was to identify the perform- ance differences between individuals VNK) have sensory and motor preservation in their lower extremities and those individuals who have no sensory and motor preservation in their lower extremities in controlling a highly critical skid control task. Specifically, the study attempted to determine if drivers with paraplegia differed from those without paraplegia (T4-Tl2) in performance of a behind-the-wheel skid control task. The study used a rear wheel braking skid to determine if drivers could control the skid by use of countersteering. A secondary purpose of the study was to determine if a per- formance difference existed in the ability of all drivers to control rear wheel braking skids to the right or to the left. Importance This study will indicate if drivers with paraplegia can compensate for less-than-optimal levels of sensory and motor abilities. McKnight (26) indicated proprioception to be an important character- istic in detecting and controlling skids. Little (4) also cited that an intact sensorimotor system appeared to be necessary for safe driving. Drivers with paraplegia in this study had complete spinal cord injuries that eliminated all sensory and motor preservation and proprioception below the Spinal cord segment that corresponds with the vertebral body level. Without the conduct of studies such as this, it would not be possible to determine if minimal levels of sensory and motor preser- vation and proprioceptive characteristics can still provide drivers with the ability to detect and control a highly critical skid control task. General Questions to Be Answered This study attempted to answer the following questions: I. Does a difference exist between able-bodied drivers and drivers with paraplegia in the ability to control a rear wheel lockup skid? 2. Does a performance difference exist in the ability to control a rear wheel lockup skid to the left or to the right for all drivers? Methods of Procedures The use of skid pan instructional facilities is in operation throughout the country. The primary purpose of a skid pan is to allow drivers to experience both vehicular and driver control limitations and capabilities on a surface that simulates potentially hazardous environmental conditions. This controlled experience provides perceptions into (I) the seriousness of a skid, (2) the driver and vehicle susceptibility to a skid, (3) the personal efficacy of coun- termeasures, and (4) the response efficacy of countermeasures. Fourteen drivers with spinal cord injuries (T4-Tl2) volun- teered to participate in the study. The able-bodied group was matched to the paraplegia group based on years of driving experience. In addition, both groups had no experience in actual behind-the-wheel skid control programs and at least a minimum of two years driving experience. During May of l98l, 28 volunteer drivers were asked to par- ticipate in the behind-the-wheel skid control exercises. The data collected consisted of (l) uncontrolled or (2) controlled evaluations for 16 individual rear wheel lockup skids that alternated between the initial direction of left or right. The first trial direction was randomly selected. All drivers used the same vehicle and were given identical familiarization exercises in order to become acquainted with the vehicle's acceleration, braking, and steering characteristics. A speed range was established between 34 and 38 miles per hour and confirmed by radar. The data collected from the evaluations were analyzed using t-test and post hoc ANOVA statistical procedures. Basic Assumptions The investigation of the preceding questions was based on the following assumptions: l. All licensed drivers with or without disabilities may be involved in a skid. 2. Skids occur in both the right and left directions. Definition of Terms Able-bodied--person having no physical or known mental dis- abilities. Cervical vertebrae--the seven vertebrae in the neck area of the backbone (C-6 means the sixth vertebra from the head) (47). Criticality--the impact an objective has upon the overall transportation system (27). Disabilitye-a limiting condition in a person which may be either physical or mental and which can be described medically (22). Functional characteristics--special, normal, or proper action of any part or organ of the body (47). High criticality:-an item a driver must know if he is going to successfully perform the driving task within the highway transporta- tion system (27). Lesion level--the area of the spinal cord that has been injured or become diseased (22). Lumbar vertebrae--the five vertebrae in the abdominal area of the backbone (L-5 means the 24th vertebra from the head) (47). Motor abilities--capability for a muscle, nerve, or center to affect or produce movement (47). Paraplegia--complete paralysis of both legs and the lower part of the trunk (47). Proprioception--reception of stimuli within the tissues of the body, as within muscles and tendons (47). Sensory abilities--capability of the body to respond to a physical stimulus (light, heat, pressure, etc.) by generating an impulse (47). Skjg:-a slipping or sliding effect which may result from (I) one or more wheels being locked by excessive braking, (2) sudden or excessive steering which breaks the normal traction between the tires and the road surface, or (3) excessive acceleration which causes the drive wheels to spin; or the errant vehicular motion(s) which may take place when the wheels simply lose traction on a slick surface, without the driver having taken any wrong action (3). Special populations--groups of individuals who have unique characteristics related to functional capabilities and whose learning needs may best be met through specially designed curricula, through special supplements or alternatives to portions of regular instruc- tional programs, and/or through the unique educational services of specialized personnel (3). Thoracic vertebrae-~the l2 vertebrae in the chest area of the backbone (T-6 means the l8th vertebra from the head) (47). Delimitations The delimitations of this study were as follows: l. The study was conducted only on drivers with paraplegia who had spinal cord injuries that were complete. 2. The study was conducted on drivers with spinal cord injuries T4 through Tl2. 3. The drivers with paraplegia in the study were volunteers solicited through the National Spinal Cord Injury Foundation mailing list in southern Wisconsin. 4. Drivers with paraplegia had at least two years of familiarization and experience with hand controls and assistive devices in the operation of the vehicle. 5. Drivers did the majority of their driving in southern Wisconsin and/or northern Illinois. Limitations The limitations of this study were as follows: l. The drivers used in this study were not randomly selected. 2. The drivers' experiences with skid involvement were unknown. 3. The drivers' informal learning experiences with skid control were unknown. Possible Application Identification of performance differences will serve as support data for inclusion, modification, or exclusion of skid con- trol content components in future driver education instructional pro- grams for special populations. Organization of the Study Chapter 11 presents a review of literature from the follow- ing areas: accident experience of handicapped and able-bodied drivers, impact of skid involvement on the transportation system, physical functional characteristics of persons with paraplegia, and a review of existing curriculums for driver education instructional programs. In Chapter III the design and methodology of the study are presented. Chapter IV presents the analysis of the data for the study, and Chapter V contains a summary of findings, conclusions, recommenda- tions, and a discussion. CHAPTER II SURVEY OF RELATED LITERATURE Special Driver Populations Recent developments have motivated special populations of persons to learn to drive. Among the developments were engineering advancements, innovative and specialized education programs, and legislation that promoted equal opportunities for special populations. Legislatively, Title V of the Vocational Rehabilitation Act of 1973, Section 503, directed affirmative action to employ the physically disabled. This indirectly required the physically disabled person to have transportation. Although public transportation was increas- ing in availability and often suggested as a solution, personally owned vehicles have advantages in economic, educational, and recrea- tional activities that far outnumber the advantages of public trans- portation. For this reason, most persons with disabilities preferred driving a private vehicle (l, 20). The ability to own and operate a vehicle provided increased independence and mobility for persons with disabilities. The most recent educational legislative provision was the Education for All Handicapped Children's Act (Public Law 94-l42). This law mandated that every school system in the nation must make provisions for a free, appropriate public education for every child between the ages of 3 and 21, regardless of how or how seriously the TO ll person may be disabled. Among other things, this meant public schools that offered driver education courses must by law allow students with physical disabilities to enroll in the driver education course, even though the teachers may not be adequately prepared in understanding the associated physical limitations of the students. This increased enrollment in established driver education programs necessitated increased awareness and concern for proper evaluation, individualized instruction, and effective use of assistive devices (23). Most efforts have been channeled into improving evaluation techniques and selecting effective assistive devices. Research has been less active in assessing limitations and capabilities of psycho- motor performance for specific physical disability diagnoses. It was the driver's performance more than anything else that seemed to determine how effectively the highway transportation system would operate (40). In a study conducted at the Indiana University Institute for Research in Public Safety, human errors were identified as definite causes in 70.7 percent of the accidents, environmental factors in l2.4 percent, and vehicular factors in 4.5 percent. In 20 percent of the accidents no definite cause could be identified (38). Additionally, the need for special equipment and the nature of various disabilities caused some people to question whether handicapped individuals could drive safely. Considering physical types of defects, those involving the extremities appeared pertinent for study (4). l2 The study of Crancer and McMurray (8) found that drivers with disablement of extremities had a significantly higher accident frequency than the total population average of the State of Washington. A more recent study conducted through the Division of Research in the State of New York (28) concluded that drivers using "full hand con- trols" because of a disability of both feet, legs, or parts of legs missing or unable to function had a higher accident rate than other drivers. This was contrasted by a study conducted by the University of Denver that surveyed over 400 national licensing and safety pro— fessionals regarding evaluation of the driving abilities of physically impaired drivers (l3). In the survey, physically impaired drivers were reported to be safer than nonimpaired drivers. Another study found l0 of 13 of the largest insurance companies viewed the handi- capped driver as a better risk than the able-bodied because of his extra care and caution (34). In a study by Ysander, 494 disabled drivers, the majority having loss of function in the legs, were evaluated with respect to the frequency of road accidents and serious traffic offenses during a 10-year period. Disabled drivers were not found to be an increased hazard (42). Additional studies also have produced conclusions that physically disabled drivers had no difference or decidedly lower accident rates than their nondisabled counterparts (l0, l6, ll, 42). In a recent technical summary on Human Factor Analysis of Automotive Equipment for Disabled Drivers, the authors stated: "The consensus is that disabled drivers that use special equipment pose no greater l3 safety hazard on the road than able-bodied drivers that are matched demographically" (18). Furthermore, a study that surveyed the evaluation, selection, and training methods for driver education and the physically disabled stated that "except at the lowest extremes, psychophysical deficien- cies are not associated with accidents and violations in a significant degree" (l5). The Texas Transportation Institute in its study examined per- formance and concluded the use of common hand controls did not affect driver performance to any appreciable degree (l8). While prior research strongly suggested that handicapped drivers had a somewhat higher accident potential than able—bodied drivers, it also indicated disabilities can be satisfactorily com- pensated for by the individuals involved to the extent that they became equal to or better than able-bodied drivers (42, 36). However, the compensation characteristics provide no measurable indication of psychomotor ability levels. Data provided in accident-record studies were neither particu- larly controlled nor conclusive since few distinguished among neuro- logically, orthopedically, or medically disabled drivers (l6). Most literature on this subject also failed to distinguish severity levels. Furthermore, "almost every condition that is a diagnostic entity known to the medical profession could conceivably at some time or in some degree interfere with the safe operation of a motor vehicle" (4). There also existed little data on interrelationships of driver capa- bilities on the disabled driver, vehicle, and roadway in occurrence 14 of accidents (20). The review of studies based on driver accident records did not approach the question of driver performance but rather of accident experience. The research needs for advanced driver education activities, which included special populations, stated that other criteria were recommended to be used, at least in part, as a substitute for accident data (2). Sensorimotor System and Functional Characteristics Driving is a task requiring certain levels of sensory abili- ties that include vision variables, kinesthetics, perception, and tactile senses (22). An intact sensorimotor system appeared to be necessary for safe driving, and therefore impairment of senses and the motor system by physical defects and handicaps must be considered as a potential contributor to accidents (4). Vision may be the most important factor in providing cues to guide a driver in traffic. Studies stated at least 90 percent of driver input originated through the sense of vision (31, 39, 40). Hofkosh stated after studying the role of vision that the field of vision was not so much a problem as how a driver used the vision (15). However, the particular roles of the other senses were not clearly defined (4). Little has been done to investigate what cues motorists actually used in detecting or avoiding a skid (30). The emphasis away from visual and toward sensory importance was noted in the skid control task where perception of the skid has been related primarily to kinesthetic and proprioceptive cues rather than visual cues (26). l5 Direct injury to the Spinal cord results in impairment of motor and sensory function at the level of injury and below. The degree of motor and sensory loss depends on the level of the injury in the spinal cord and the extent of damage at that level. Complete severance of the spinal cord results in a complete lesion, which immediately produces sensory and motor paralysis (5). Motor paraly- sis is characterized by loss of voluntary muscle function. Sensory paralysis abolishes sensory appreciation of pain, temperature, touch, and tactile discrimination and position (5). An individual with a spinal cord injury in the cervical (C) area is described as a quadriplegic when there is impairment in all four extremities and trunk musculature. An injury in the thoracic (T) and lumbar (L) sacral area results in paraplegia or impairment of the lower extremities and trunk musculature (see Figure l). The lower the level of injury, the greater amount of muscle function available to the spinal cord individual. At level T1 and below there exists normal upper extremity muscle function, that is, completely normal arms and hands. Skid Control There are two basic behavior processes required of the driver, according to Michaels' study of human factors: (1) information processing and (2) control responses (43). A driver's ability to react appropriately to a skid not only involves information process- ing or perception as it is commonly called but also psychomotor skill application to control the skid. The Guide for Teacher Preparation in Driver Education stated: l6 Those subjects used in the study ranged from T4 through T12. Key: cervical thoracic lumbar sacral (Dr-40 Figure l.--Vertebra1 column 17 The motor coordinations involved in arresting a skid are among the most demanding of skill requirements imposed on drivers. Therefore, sufficient practice in executing the type of control movements which would produce recovery would seem appropriate to determine levels of performance skills (40). The importance of learning to cope with emergencies resulting from vehicle malfunctions, environmental conditions, and actions of other drivers has been emphasized by studies done by Baker and Mosely (4). Bishop concluded that 20 percent of one-car accidents involving young drivers were compounded by failure to correct a skid adequately. His review of 119 single-vehicle accidents concluded the following specific errors were predominant: 1. abrupt movements on slippery surface, 2. late correcting and/or compensating for a skid, and 3. locking of wheels which eliminated possibility of steer- ing (44). A study in Virginia found about 40 percent of all accidents reported in a one-year period involved skidding (40). In one-third of the cases the skidding occurred prior to brake application (39). In 1979, the Insurance Institute for Highway Safety reported fatal accidents on wet pavements represented 15.3 percent of all fatal accidents (46). Liberty Mutual Insurance Company identified six basic causes of skids. They were: 1. Front wheel braking skid, 2. Rear wheel braking skid, All wheel braking skid Power skid b0») 18 5. Spinout, and 6. Hydroplaning (24). It is important to note that the skids may occur before, during, or after braking inputs (4). In addition, the chances of skidding occurring increase as the road surface friction is reduced. Therefore, snow, ice, oil, water, curves, vehicle equipment, main- tenance, tires, and brakes may all be contributing factors in combi- nation with human error (27). The Driver Education Task Analysis identified five major levels of criticality that were assigned to performance objectives by a panel of highway safety authorities. The standards were: High Criticality - 95% to be performed correctly Moderately High Criticality - 85% to be performed correctly Moderate Criticality ~ 70% to be performed correctly Moderately Low Criticality - 60% to be performed correctly Low Criticality - 5 % to be performed correctly These standards were developed to represent levels of achieve- ment of a student graduating from a driver education course. As judged by the panel, the skid control task was identified as one with high to moderately high criticality (27). The combination of high frequency and high criticality of skidding indicated that driver performance in skid control is one of primary concern in the driving task. Curriculum Content Components The inclusion of skid control instructional objectives from the Driving Task Analysis and application of skid control instruc- tional units in the Safe Performance Curriculum suggested driver 19 education professionals accepted the skid control component as one that provided the driver with (l) proper knowledge and (2) sufficient practice in evaluating psychomotor skills. However, there were not any data that determined what constituted sufficient practice time for a particular skid control task. Brown stated that curriculum goals, objectives, and critical knowledge should be the same for all populations of drivers (6). Meneham Less supported this same philosophy by agreeing that adapted driver education should focus on the same instructional areas as driver education for nondisabled persons with some modifications (23). Research, however, has not been initiated to determine if skid control skills can be performed by drivers with specific physical disabilities. Evidence that illustrated deficiency in psychomotor skills by drivers with physical disabilities would have an impact on modification of procedural content components. Conversely, if evi- dence illustrated proficiency in the ability to control a skid, then inclusion would be a possible component. m A review of literature can best be summarized by stating that although accident- and violation-record studies have been done for general populations of drivers with physical disabilities, the records did not indicate experience levels for drivers with a specific diagnosis. Furthermore, assessments of skill performance levels apparently have not been studied in any systematic way to determine capabilities or limitations for including a behind-the-wheel critical 20 conflict content component such as skid control into an adapted driver education program. Chapter III presents the design, hypotheses, sample, and methodology used in the study. CHAPTER III DESIGN OF THE STUDY This study was designed to investigate the performance limi- tations or capabilities of able-bodied drivers and drivers with para- plegia in the ability to control a rear wheel skid. The procedures used in this study are explained as they relate to the rationale, hypotheses, design, sample, procedures, measures, pilot study, equipment and facilities, and statistical analysis. Rationale Most driver education programs, for either novice or experi- enced, able-bodied drivers contained a unit or devoted an entire pro- gram to critical conflict situations that a driver may encounter. Generally, these advanced driving technique units or, in many cases, programs had instruction in the following maneuvers: l. Constant cornering--This maneuver acquainted the driver with handling characteristics of vehicles during constant curves in the highway. 2. Off-road recovery--This maneuver familiarized the driver with a procedure to return safely to the intended path of travel after one or more vehicle wheels have left the paved or graded road- way surface. 21 22 3. Controlled braking--This maneuver provided the driver with the experience of utilizing specialized braking techniques used to optimize braking efficiency and vehicle control in a variety of adverse situations. 4. Evasive action--This maneuver acquainted the driver with the experience of utilizing steering capabilities of the vehicle for directional control in order that a collision is either avoided or made less severe. 5. Skid control--These maneuvers alerted the driver to steering and braking inputs that are required for controlling a vehicle in differing skid situations. Skid control tasks may have to be applied as a result of six basic causations: 1. Rear wheel brake lockup, 2. Front wheel brake lockup, 3. All wheel brake lockup, 4. Power application to drive wheels, 5. Spinout (cornering), and/or 6. Hydroplaning. Inability and inexperience to successfully master psycho- motor skills related to (l) constant cornering, (2) off-road recovery, (3) controlled braking, and (4) evasive steering may contribute to skid involvement on wet or dry road surfaces. The rear wheel brake lockup skid was selected for the simu- lated behind-the-wheel task for three primary reasons: 23 l. The skid may occur before, during, or after braking, therefore illustrating the high potential and relationship to the driving task; 2. A vehicle with locked rear wheels may behave as a very unstable system, therefore exhibiting very overt behaviors in con- trolled or uncontrolled states; and 3. The rear wheel skid control task was emphasized in all skid control programs. Since the skid control content components were emphasized in most advanced programs for able-bodied learners, it was with particu- lar interest that the skid control task be examined for applicability to a specific population of drivers with spinal cord injuries. The policies and guidelines developed for Advanced Driver Education (2) recommended that participants "should consist of both adults and youth who have demonstrated a combination of driving experience and a general knowledge of the driving task" (2). There was little debate in related literature that special populations of drivers have abilities that are sufficient for safe driving (low accident and violation involvement) even though the abilities may not be optimal (i.e., readiness, precision, efficiency, and ease in physi- cal activity) (22). It would seem reasonable to determine constraints or parame- ters of skid control skill levels for drivers with spinal cord injuries (T4-T12) in order to decide if implementation of behind-the- wheel activity was practical or even possible. 24 Estimates varied greatly on the number of persons with physi- cal disabilities. Defining or grouping persons into general classi- fications would increase the numbers of persons for study but would fail to identify specific physical limitations and capabilities that existed within a classification. The basic weakness of all classifications is that there are wide variations in individual differences in kind of involve- ment, and extent and progress of condition. The only possible approach to classification of disabilities is to organize them into functional categories and then require careful evaluation of each individual case for the assessment of limitations and potentials in the manual task of driving (22). Previous studies have not reported types of physical disabilities and, therefore, provided little information for generalizations about a specific diagnosis (13, 42, 16, 11, 28, 8). It was estimated through various government studies that the number of persons with physical limitations due to paralysis was approximately 925,000 (1). Most of the paralysis was caused by spinal cord injuries. A spinal cord injury in the cervical (C) area of the spinal column was described as a quadraplegia when there was impair- ment in all four extremities and trunk musculature. An injury in the thoracic (T) and/or lumbar (L) sacral area resulted in paraplegia or impairment of the lower extremities and trunk musculature. For this study the area of interest was limited to drivers having complete spinal cord injuries with level of lesions from the fourth thoracic vertebra (T4) through the twelfth thoracic vertebra (T12) or namely low-level paraplegia. Complete injuries were char- acterized by total loss of motor and sensory preservation below the level of lesion. In incomplete spinal cord injuries there was partial 25 preservation of motor and sensory function in varying degrees and combinations. According to Burke, complete spinal cord injuries from T1 through T12 would provide for persons to have complete normal strength and range of motion in arms and hands (5). Trunk stability would vary, depending upon the level of injury. The use of drivers with paraplegia (T4—T12) would also standardize hand-control equipment needed to aid the driver in the driving task. Hypotheses The following research questions were formulated: 1. Does a difference exist between able-bodied drivers and drivers with paraplegia in the ability to control a rear wheel lockup skid? 2. Does a performance difference exist in the ability to control a rear wheel lockup skid to the left or right for all drivers? The research hypotheses were as follows: 1. There is a difference between able-bodied drivers and drivers with paraplegia in the ability to control a rear wheel lockup skid. 2. There is a difference in driver performance in the ability to control a rear wheel lockup skid when the skid is to the left or to the right. The null hypotheses were as follows: 1. There is no difference between able-bodied drivers and drivers with paraplegia in the ability to control a rear wheel lockup skid. 26 2. There is no difference in driver performance in the ability to control a rear wheel lockup skid control task when the skid is to the left or to the right. The research design may be graphically represented as follows: Left (L) Right (R) Able-bodied 1 2 drivers (A) Drivers with 3 4 paraplegia (P) Cells MA = (l + 2) = average number of uncontrolled total skids for able-bodied drivers MP = (3 + 4) = average number of uncontrolled total skids for drivers with paraplegia ML = (l + 3) = average number of uncontrolled left skids for all drivers MR = (2 + 4) = average number of uncontrolled right skids for all drivers The experimental and null hypotheses can be represented as follows: 1 H0: MA = MP H]: MA f MP 27 M The present study employed a t-test design. Able-bodied drivers and paraplegic drivers constituted two separate groups. The two groups of drivers were subjected to 16 test trials of a rear wheel lockup skid control task. On each test trial, either with initial left or right skids, assessmentsA 44—11' 1 200' l A A l I A A , . .1 , 1F H+—-ao -—+i IP17"‘ I A AT 1 17' l l 1 710' 255' 17' A A JL w—d r ->A 4“— 11' 200' A A A A A A ‘LIL 260' r—T ‘1 'j Figure 3.--Skid pan dimensions (not drawn to scale). 38 To test the second hypothesis, which investigated if a dif— ference existed in the ability to perform a rear wheel lockup skid control to the left or to the right, the following statistical analy- sis was used. For each subject, the number of uncontrolled skids on the initial left or right skid was separately scored. Thus, two measures, one on right skids and the other on left skids, were taken from the same subject. A two-tailed t—test for two matched groups was run to determine the significance of the difference between the measures for all subjects. An additional interest was the improvement or change in per- formance as a result of the 16 practice acquisition trials between the two groups. A within and a between design was used and, therefore, tested post hoc with analysis of variance (ANOVA). M This chapter presented the methodology and design used in determining if performance differences existed between drivers with and without paraplegia in controlling a skid, and between skid direction for all drivers. Chapter IV presents the analysis of results. CHAPTER IV ANALYSIS OF RESULTS This chapter reports the findings of data relevant to (1) differences in driving experience between the two groups, (2) the relationship between driving experience and the ability to control skids, (3) the difference between groups in the ability to control a rear wheel skid, (4) the difference in initial direction of skids for all drivers, and (5) the difference between the two groups in the rate of acquiring the ability to perform a rear wheel skid task. The study used 14 drivers with paraplegia and matched 14 able-bodied drivers on years of driving experience. Each driver was evaluated on the ability to control a rear wheel lockup skid. The evaluations were measured as controlled or uncontrolled. After the evaluations were completed, the paraplegic subject with an extremely high score in number of uncontrolled skids (all skids uncontrolled) was discarded. The matched able-bodied driver's performance was also discarded. This matched pair was dropped to minimize variability that would result with a small sample. The analysis of results is based on 13 pairs of matched subjects. Matched Subjects Presented in Table 1 are the data on driving for the two groups. The table indicates that the paraplegic group had a range of 39 40 2 through 38 years driving experience. The mean was 14.8462, with a standard deviation of 9.616. The range for able-bodied subjects was 2 through 36 years driving experience. The able-bodied group had a mean of 14.154, with a standard deviation of 8.523. Table l.--Years driving experience. Paraplegic Able-Bodied Years Driving Experience Years Driving Experience 2 2 5 5 7 9 8 10 10 ll 11 12 13 12 17 l4 l8 14 19 18 20 19 25 22 38 ‘36 Total 193 184 7' 14.8462 14.1538 s.d. 9.61636 8.52297 H0: MA = MP H]: MA f Mp “g: = 24 Computed t_= .194257 Tabled t_ = :2.064 p_= .05 Decision: failed to reject 41 The first analysis conducted was a tftest to determine if a significant difference existed between the matched groups in years driving experience. The results of the analysis indicated a 3(24) = .1943 with p_= .84167. An absolute t_value of 2.064 was needed to reject the null hypothesis at the .05 significance level. The analy- sis indicated no significant difference existed between groups in years driving experience. Years Driving Experience and Performance Correlation Since the subjects in the two groups were matched on previous driving experience, one can assume that this variable was randomly distributed across the treatment variables. As a check, however, to examine the correlation between years of driving experience and the number of uncontrolled skids over the 16 acquisition trials, a Pearson product-moment coefficient of correlation was computed between the two dependent measures for all subjects. The correlation coefficient was found to be Y (24) = .396, p_< .025 in a two-tailed test. The critical v was .388. This indicated as the years of driv- ing experience increased so did the number of uncontrolled skids. Table 2 displays the data. If the groups were examined separately, the coefficient of correlation for the paraplegic group was .537, p_< .05. The critical 7 needed for significance was .476, one-tail test. This correlation strongly indicated as a group the subjects with paraplegia increased in the number of uncontrolled skids as the years of driving experi- ence increased. 42 The coefficient for the able-bodied group was .357, p_< .05. The critical v needed for significance was .476, one-tail test. This indicated no significant difference between years of driving experi- ence and the number of uncontrolled skids. Table 2.--Years driving experience and number of uncontrolled skids. Paraplegic Number of Able-Bodied Number of Years Driving Uncontrolled Years Driving Uncontrolled Experience Trials Experience Trials 2 2 2 -- 5 2 5 l 7 l 9 l 8 4 10 1 10 5 ll -- ll 1 12 1 l3 1 12 -- l7 3 14 l 18 3 l4 -- 19 2 18 -- 20 1 19 25 3 22 38 7 36 1 Total 35 10 y = .396 p_< .025 Group Difference Analysis A t:test was used to determine if a difference existed between drivers with paraplegia and able-bodied drivers in the ability to con- trol a rear wheel lockup skid. Table 3 displays the data for this 43 analysis. The paraplegic group had a mean of 2.6923, with a standard deviation of 1.7974, and the able-bodied group had a mean of .7692 and a standard deviation of .7250. The results of the t7test indi- cated a 3(24) = 3.5775, p_= .0018. A t_of i 2.064 was needed to reject at the .05 level; therefore, the null hypothesis of no signifi- cant difference between drivers with paraplegia and able-bodied drivers to control a rear wheel skid was rejected. Table 3.--Group difference in number of uncontrolled trials. Number of ngpée Uncontrolled 7' s.d. Trials Paraplegic 13 35 2.6923 1.7970 Able-bodied _13_ _10_ .7692 .7250 Total 26 45 H0: MP 3 MA H]: MP # MA gj.= 24 Computed t = 3.5775 Tabled t_— = :2.064 p_= .05 Decision: reject Skid Direction Analysis A tgtest was used to determine if a performance difference existed in the ability to control a rear wheel skid to the left or to the right for all drivers. Table 4 displays the data for this analysis. The results of the analysis indicated a t_of -.1496, 44 p_= .8768. A t_of i 2.060 with gj_= 25 was needed to reject at the .05 level. Therefore, the null hypothesis was retained. 0n the basis of the obtained t value, no significant difference existed between the number of uncontrolled skids to the left or to the right for all drivers. Table 4.--Skid direction analysis. Number of ngple Uncontrolled 7' s.d Trials Uncontrolled left skids 26 22 .846154 .967153 Uncontrolled right skids 26 23 .884615 1.142870 H0: MP = MA H]: MP # MA df_= 25 Computed t_= .149604 Tabled t = :2.060 p_= .05 Decision: failed to reject Acquisition Analysis Because the previous statistical analyses revealed signifi- cant differences between drivers with paraplegia and able-bodied drivers in the ability to control rear wheel skid, a follow-up analysis was conducted. The follow-up analysis of variance found significant differences at the .05 level in (1) the trial effect, (2) the group effect, and (3) the group-by—trial interaction effect 45 for drivers with and without paraplegia in acquiring the ability to control the rear wheel skid. Table 5 is a summary of the ANOVA used in this analysis. Table 5.--ANOVA for drivers with and without paraplegia in acquisition ability. Source of Variation §§ gf- fl§ E. .2 Group (G) 1.5024 1 1.5024 12.7982 p_< .005 Error (b) 2.8173 24 .1174 -- -- Trial (T) 10.0938 15 .6729 10.3808 p_< .005 Trial x group (T x G) 2.3822 15 .1588 2.45 p_< .005 Error (w) 23.3364 360 .0648 -- -- Total 40.1323 415 Figure 4 presents the number of uncontrolled skids for the paraplegic and able-bodied groups over the 16 acquisition trials. Each plotted point on the graph represents the total number of uncontrolled skids on a particular trial by a group. This figure indicates as a group the paraplegic drivers acquired the ability to perform the skid control at a slower rate than the able-bodied driv- ers. It also indicates that as the number of trials was increased, both groups decreased in the number of uncontrolled skids. 46 spins pallouiuooun go uoiquodoud oooo. Pmmo. mmmp. womm. wnom. cvmm. mpmc. mmmm. cmpo. mmmo. Nmom. Noam. Pmmm. oooo.p ‘I .pumwmm Pave“ vcm azocu--.< mczmwm NF d 18w 8 8 umwuonbzm olllo uwmmpamcma 811111. x P— ’1 “ op m #1 LwnE22 mech m L 1 8111481114®11|®7flflfl1|1 x I0 "l *1 11 «P qr / /\ L l 4 OQQNKDLDG _L NF mp spixs pallouuuooun go JaqwnN 47 Summary This chapter reported the results of the data as analyzed. Raw data relating to the results are contained in Appendix H. Chapter V presents findings, conclusions, recommendations for future research, and a discussion. CHAPTER V FINDINGS, CONCLUSIONS, RECOMMENDATIONS, AND DISCUSSION Summary The central purpose of this study was to determine if drivers with or without paraplegia (T4-T12) differed in the ability to control a rear wheel skid. A secondary purpose of the study was to determine if a difference existed in the ability for all drivers to control a rear wheel skid to the right or to the left. A review of literature indicated that (l) accident and viola- tion record studies have been done for general populations of drivers with disabilities, but did not indicate the experience of drivers with specific disabilities; (2) assessment of the ability to perform a critical skill had not been studied for persons with specific diag- nosed disabilities; (3) an intact sensorimotor system appeared to be necessary for safe driving; (4) driver performance in skid control was a primary concern in the driving task; and (5) there were no data to indicate the number of recommended training trials for skid control instruction. Fourteen drivers with spinal cord injuries (T4-T12) volun- teered to participate in the study and were matched with 14 able- bodied drivers based on years of driving experience. The driver performances of 13 drivers were evaluated as controlled or uncon- trolled for 16 separate rear wheel lockups that alternated equally 48 49 between the initial direction of left or right. All drivers were evaluated at a skid pan facility and used the same vehicle equipped with special skid-inducing equipment. The data were analyzed with t-tests to determine if differ- ences existed for ability levels and direction. An ANOVA was used in a follow-up statistical analysis for determining group and trial acquisition rates. Findings The major findings of this study were: 1. There was a significant difference between able-bodied drivers and drivers with paraplegia in the ability to perform a rear wheel lockup skid control task. Able-bodied drivers had fewer uncon- trolled skids than drivers with paraplegia. 2. There was no significant difference in driver performance in the ability to control a rear wheel lockup skid when the skid was to the left or to the right. 3. There was a significant difference in the number of con- trolled skids for all drivers as the acquisition trials increased. All drivers increased the number of controlled skids as acquisition trials increased. 4. There was a significant difference in the rate of acquisi- tion between the paraplegic group and the able-bodied group. Para— plegic drivers made more uncontrolled skids than the able-bodied over 16 trials. 5. There was a significant positive correlation between years of driving experience and the number of uncontrolled skids for 50 all drivers. This indicated as the years of driving experience increased so did the number of uncontrolled skids. 6. There was a significant positive correlation between years of driving experience and the number of uncontrolled skids for drivers with paraplegia. As a group, drivers with paraplegia decreased in the ability to control a skid as years of driving experience increased. 7. There was not a significant correlation between years of driving experience and number of uncontrolled skids for able-bodied drivers. This indicated there was no significance between years of driving experience and the number of uncontrolled skids. Conclusions The following conclusions are based upon the findings of the study: 1. Drivers with paraplegia will make more errors and will require more trials than able-bodied drivers, but they can learn to control a rear wheel skid. 2. Both paraplegic and able-bodied drivers improved in their ability to control rear wheel skids with increased practice. 3. The direction of the skid, whether left or right, makes no difference in the ability of drivers with paraplegia and able- bodied drivers to control the skid. 4. Experienced paraplegic drivers had more difficulty in controlling skids than drivers with fewer years of driving experience. This was not the case for able-bodied drivers. For able-bodied driv- ers, the number of years of driving experience made no difference in the ability to control a skid. 51 Recommendations The following recommendations are based on the observations, findings, and conclusions of the study. 1. Drivers with spinal cord injuries (T4-T12) should be per- mitted to participate in behind-the-wheel skid control instruction. 2. Skid control instruction activities should include rear wheel skids to the left and to the right. 3. Drivers with spinal cord injuries (T4-T12) should be allowed more training trials in skid control than able-bodied drivers. 4. A11 drivers with many years of driving experience should be made aware of possible limitations and capabilities in controlling a skid. This awareness may be accomplished through a variety of pub- lic information and instructional programs. Recommendations for Further Research 0n the basis of the data from this study, the following are recommendations for further research: 1. A study should be conducted to compare the effect of dif- ferent assistive steering devices for controlling a rear wheel skid for drivers with spinal cord injuries (T4-112). 2. Replication of this study to compare the ability of drivers with other specific diagnosed disabilities and able-bodied drivers to control a rear wheel skid. 3. A study should be done to compare the braking capabilities of drivers who use hand controls and able-bodied drivers. 4. Additional research should be conducted to compare the ability of drivers with specific diagnosed disabilities and able-bodied 52 drivers to control a vehicle in a controlled braking exercise, evasive steering exercise, and off-road recovery exercise. 5. Replication of this study should be done to compare the ability to control a rear wheel skid for novice drivers with specific diagnosed disabilities and novice able-bodied drivers. 6. Additional research should be conducted to determine what type of cognitive information or preparation can increase the ability of a driver with a specific diagnosed disability to control a rear wheel skid. Discussion This study addressed the potential for instructional use of ' critical driving situations with special p0pu1ations of drivers. It specifically identified that the rear wheel skid control task can be performed by drivers with paraplegia although at a slower rate com- pared to able-bodied drivers. Extensive survey of printed materials revealed there had been no research data until the present investigation that could support inclusion or exclusion of the behind-the-wheel skid control partici- pation by drivers with physical disabilities. Most curriculum com- ponents such as skid control had been based on subjective decisions that involved (1) the perceived risk of the activity and (2) the perceived potential ability of a disability group. The Policies and Guidelines for Driver Education stated the objectives for persons with physical disabilities should be the same as the majority popula- tion (2). This should apply to the classroom, simulation, range, and 53 behind—the-wheel instructional objectives. This study supported the inclusion and modification rather than the exclusion of behind-the- wheel skid control activities for drivers with paraplegia (T4-T12). The study also suggested driver education programs that had been designed for special populations of drivers with a wide range of dis- abilities should have a curriculum that can provide highly critical driving tasks such as skid control to those students with sufficient abilities or compensatory skills. Any student should not be restricted from participating in an instructional activity, such as skid control, solely on the basis that not all students may attain the desired behav- ior or cannot acquire the skill at the same rate. The subjects with paraplegia in the present study were spe- cifically restricted to complete spinal cord injuries (T4-T12) because of the complete loss of motor and sensory characteristics in the lower extremities and trunk musculature. McKnight indicated that "percep- tion of a skid is dependent primarily upon proprioceptive or kines- thetic cues rather than visual cues"; however, subjects with para- plegia were lacking all proprioceptive or kinesthetic ability in the lower extremities and varying positions on the trunk. This indicated that essential proprioceptive and kinesthetic abilities may be located in the upper extremities, or other compensatory cues, such as visual cues, may be involved to a larger extent than had been previously recognized. During the study it was observed that the majority of para- plegic drivers using hand-control equipment maintained the left hand on the control lever in order to be prepared to using braking or 54 acceleration inputs. This meant the majority of the skids experi- enced by drivers with paraplegia were countersteered with only one hand (palming) in comparison to able-bodied drivers who generally used a two-hand technique (hand-over-hand). This method difference of providing countersteering inputs to the vehicle may have had an influence on the ability to control the skid and the rate at which the drivers learned to control the skid. It was also noted that two drivers with paraplegia used an assistive steering device such as a spinner knob to assist with the steering input. The sample was too small, however, to infer any control difference between use of the spinner knob or the palming technique for drivers with paraplegia. Of special concern was the philosophy and objectives of skid control instructional programs. The objectives for various novice and experienced driving programs differed from mastery to experiential and therefore provided a wide range of training trials. This dis- similarity among programs confounded any attempt for literature to recommend a standardized number of training trials. Additionally, the angle and speed the instructional vehicle entered a skid pan defined the degree of difficulty in the ability to control a skid. Other factors that are considered as influencing factors on the skid diffi- culty are wheel base, drag factor, and duration of brake lockup. The latter factor, duration of brake lockup, was utilized to the fullest extent in the study to ensure that drivers would be assessed for their ability to countersteer for primary and secondary skids. Many other programs limited rear wheel lockup so a driver had no real opportunity to demonstrate countersteering proficiency, while others demanded 55 students to induce the rear wheel skid by themselves. This study required the driver to concentrate only on the countersteering input. From the analysis of results it is suggested that able-bodied, experienced drivers should receive a minimum of seven training trials, while experienced drivers with paraplegia (T4-T12) should receive at least nine training trials under similar conditions of the study. Literature has indicated a rear wheel skid as having a very unstable vehicular behavior with potential serious property damage and personal injury. Drivers, therefore, should be given sufficient opportunities to illustrate competencies rather than restricted to experiential trials. To do this, it may be necessary to restructure the priori- ties of behind-the-wheel skid activities. This may include concen- tration on one type of skid control exercise, such as rear wheel, rather than the customary exposure to a variety of skids. Accident-causation data had not identified a particular skid direction that was more prevalent; therefore, it was assumed that skids had equal probability to occur to either the left or to the right for all drivers. The use of skids to the left and to the right seemed well supported in this study. There was no significant difference in the number of uncontrolled skids to the left or to the right. This supported a conclusion that skid instruction should be presented in both directions. Exposure to skids in both directions may lead to identification of individual trends in limitations and capabilities to which drivers should be alerted in order to adjust related driving behavior. 56 In summary, performance abilities and acquisition rates have been demonstrated as different for drivers with paraplegia (T4-T12) and able-bodied drivers in controlling a rear wheel skid. Since the skid control task was rated as a highly critical driving task, instruc- tional programs should include or modify skid control curriculum com- ponents (classroom, simulation, range, and behind-the-wheel) to reflect the capabilities and limitations of drivers, especially those drivers with spinal cord injuries (T4-T12), previously omitted from behind- the-wheel skid control participation. BIBLIOGRAPHY 57 10. ll. 12. BIBLIOGRAPHY American Automobile Association. The Handicapped Drivers' Mobility Guide. N.p.: 1978. American Driver and Traffic Safety Education Association and Association of State Supervisors of Safety and Driver Education. Proceedings of the Sixth National Conference on Safety Education. Volume 11. December 1980. Proceedings of the Sixth National Conference on Safety Education. Volume IV. December 1980. Arthur 0. Little, Inc., for the Automobile Manufacturers Associa- tion. The State of the Art of Traffic Safety. June 1966. Burke, David C. Handbook of Spinal Cord Medicine. New York: Raven Press, 1975. Brown, E'lise 8. "Driver Education for the Physically Handi- capped." Journal of Traffic Safety Education, January 1975, p. 22. Colverd, Edward C., and others. Teacher's Preparation Course in Driver Education for the Physically Disabled. New York: Human Resources Center, 1978. Crancer, A., and McMurray, L. "Accident and Violation Rates of Washington Drivers With Medical Licensing and Driving Restric- tions." Division of Research, State of Washington, Department of Motor Vehicles, 1967. Des Moines Public Schools. Driver Education Curriculum Guide for the Physically Handicapped. April 1973. Comey, R. G., and Duckworth, J. E. "Comparative Study of Highway Accidents Among 625 Physically Impaired Licensees Matched With 625 Non-Impaired Licensees." Harvard School of Public Health, 1963. Dreyer, Dell R. PhysicallyHandicapped Drivers: A Comparative Study of Driver Records. Research Report 42. State of Cali- fornia, Department of Motor Vehicles, May 1973. "Edward Frye Readability Formulae.“ Journal of Reading, April 1968, p. 513+. 58 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 59 FIOPSIIVGV. S. G. "The Accident Involvement and Driving Capa- P‘llties 0f PhYsically Impaired Drivers." University of Denver College of Law, 1969. Forbes, T. W. "Driver Knowledge, Judgment and Responses in Causation and Control of Skidding." Presentation at First Inter- national Skid Prevention Conference. September 1958. Hofkosh, Jack M.; Sipajlo, Jiri; and Brody, Leon. "Driver Edu- cation for the Physically Disabled.“ The Medical Clinics of North America 53 (May 1969): 685-96. Hymen, Mary Louise. "Hand Control Drivers: Comparison of Driving Records and Insurance Rates With Those of Non-Restricted Drivers." Archives of Physical Medicine and Rehabilitation 55(10) (1974): 443-47. Koiter, W. T., and Pacejka, H. B. "Skidding of Vehicles Due to Locked Wheels." Handling of Vehicles Under Emergency Conditions. Proceedings of the Institution of Mechanical Engineers, Vol. 183, Part 3H, 1968. Koppa, Rodger J., and others. Technical Summary: Human Factors Analysis of Automotive Adaptive Equipment for Disabled Drivers, DOT-HS-8-02049, October 1980. Kramer, D. G. Driver Education for the Handicapped. Menomonie, Wisconsin: University of Wisconsin-Stout, 1976. Lehneis, H. R. "The Safety Achievements of the Disabled Driver." Biomedical Engineering 8 (October 1973): 438-39. Less, Menahem, and others. Evaluating Driving Potential of Persons With Physical Disabilities. New York: Human Resources Center, 1978. Hand Controls and Assistive Devices for the Physically Disabled Driver. New York: Human Resources Center, 1977. Teaching Driver Education to the Physically Disabled. New York: Human Resources Center, 1978. Liberty Mutual Insurance Company. "Skid Control." McFarland, Ross A. An Evaluation of the Ability of Amputees to Operate Highway Transport Equipment. Boston, Mass.: Harvard School of Public Health, 1968. McKnight, A. James, and Adams, Bert B. Driver Education Task Analysis, Volume 1: Task Descriptions. Department of Transporta- tion, HS 800367 (HUMRRO Technical Report 70-103). November 1970. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 6O McKnight, A. James, and Hundt, Alan G. Driver Education Task AnalySIS, Volume III: Instructional Objectives. Department of Transportation (HUMRRO Technical Report 71-9). March 1971. Negri, 0. Barry. “Accidents Involving Handicapped Drivers." givizipn of Research, New York State Department of Motor Vehicles, are 978. The National Research Council. "Science and Technology in the Service of the Physically Handicapped." Vol. 1. Washington, D.C.: National Academy of Sciences, Committee on National Needs for Rehabilitation of the Handicapped, 1976. Olson, Richard A. "The Driver as Cause or Victim in Vehicle Skidding Accidents.“ Accident Analysis and Prevention, Vol. 10, pp. 61—67. Rhoads, Milton 0. "The Handicapped and the Driving Task." Address at the Society of Automotive Engineers Meeting, May 14-18, 1973. Rudolf Flesch. How to Test Readability. New York: Harper & Row, 1951. Southwest Center for Safety, Oklahoma State University. Steps for Teaching the Physically Handicapped to Drive. July 1970. State Committee on Driver Education for the Handicapped, Oklahoma State Department of Education. Driver Education for the Handi- ggpped Curriculum Guide. 1973. State Motor Vehicle Department, State of Connecticut. Some of Our Best Drivers. March 1970. U.S. Department of Transportation. The Driver Education Evaluation Program Study (DEEP). Washington: Government Printing Office, July 1975. Thompson, Richard R. "Evaluating the Driving Potential of the Handicapped Using a Simulator." SAE Technical Paper Series, No. 800421. February 1980. Treat, John R. "A Study of Precrash Factors Involved in Traffic Accidents." The HSRI Research Review 10,11 (May-June/July-August 1980). U.S. Department of Transportation. National Highway Traffic Safety Administration. Guide for Teacher Preparation in Driver Education: Driving School Edition. Washington, D.C.: Government Printing Office, July 1974. 40. 41. 42. 43. 44. 45. 46. 47. 61 . Guide for Teacher Preparation in Driver Education: Secondary School Edition. Washington, D.C.: Government Printing Office, July 1974. Waller, Julian A. Guide for the Identification, Evaluation and Regulation of Persons With Medical Handicaps to Driving. The American Association of Motor Vehicle Administrators, 1967. Ysander, Lars. Sick and Handicapped Drivers. Stockholm: 1970. Michaels, R. M. Human Factors in Highway Safety Traffic Quarterly 15(a) (1961): 586-99. Bishop, Richard W. One Car Accidents and the Young Driver. Safety and Traffic Division, Automobile Club of Michigan, 1963. Titzkowski, Thomas A. "Advanced Driving Technique Project." State of Wisconsin, Project No. 00-08(080)O6-76A, April 1977. Insurance Institute for Highway Safety. "Status Report." Vol. 15, no. 17, November 21, 1980. Stedman, Thomas Lathrop. Stedman's Medical Dictionary. Baltimore: Williams and Wilkins, 1976. J . APPENDICES 62 APPENDIX A INTRODUCTORY LETTER TO SELECTED MEMBERS OF THE NATIONAL SPINAL CORD INJURY FOUNDATION 63 64 NATIONAL SPINAL CORD INJURY FOUNDATION 5261 N. Port Washington Rd. Milwaukee, WI 53217 (414) 963-0620 (VOICE & TTY) (formerly National Paraplegia Foundation) September, 1980 Good Morning, From time to time university and college students in health care, communication, design and engineering fields come to us for assistance in research or class projects. They need people with disabilities to interview or answer questionnaires. We want very much to be able to assist when at all possible. These students can learn best from you. I would like to explain the Foundation's policy in these situa- tions and ask for your cooperation. Our policy is as follows. 1. The student delivers the materials for mailing. The chapter office staff identifies the target group desired, addresses the materials and mails. The identification of the target group is not given to the student. 2. There is no obligation on the part of the disabled person to be part of a research or class project. Thank you in advance for your cooperation. Sincerely, Ellen D. Daly : State Resource Coordinator EDD:jt 65 UNIVERSITY OF WISCONSIN - WHITEWATER lfliwhathw9ndflwmumn~nVWxann53KB (kflkanoIEducoHon Dear Friend: As a faculty member from the Department of Safety Education at the University of Wisconsin—Whitewater, 1 am conducting a research study involving skid control performance of drivers. The study should provide information as to whether educational programs need to include, exclude, or modify skid control concepts in formal classes. For this purpose, I am seeking volunteer drivers with paraplegia (levels 14 through T12) to participate in a behind—the-wheel activity. Each driver will be required to attend a short classroom briefing (15 minutes) followed by a series of behind-the-wheel experiences (approximately Ii hours) on an off-street driving facility using our instructional vehicles. The skid facility is located at the University of Wisconsin-White- water and a time during Spring 1981 will be arranged to accommodate personal schedules for days, evenings, or weekends. If several people are interested, group schedules may be arranged. Interested drivers should have experiences with right-angle hand controls and be licensed drivers. Participation requires the enclosed questionnaire to be completed and returned. If you have any questions, please feel free to contact me. Sincerely, Thomas A. Titzkowski Department of Safety Education TAT/chr APPENDIX B ABLE-BODIED AND PARAPLEGIA QUESTIONNAIRE 66 67 Paraplegia Questionnaire Name: Address: City: Phone: Sex: M or F (Please circle) Age: Level of lesion: T4 T5 T6 T7 T8 T9 T10 T11 T12 Other Age when injury occurred: Were you licensed to drive before your injury? yes no (Please circle) Years driving experience before injury: Years driving experience after injury: Years driving experience total: Have you had high school driver education before injury? yes no (Please circle) Have you had driver education after your injury? yes no (Please circle) Have you had actual skid control training behind the wheel? yes no If yes, before injury after injury both (Please circle) 68 What type of hand controls do you use? right angle push pull motorcycle grip other What type of steering device do you use? spinner knob none other The state where you have done the majority of driving after injury: Number of reported accidents since you began driving: 0 l 2 3 4 5 or more Number of moving traffic violations since you began driving: 0 l 2 3 4 5 or more Estimate of annual mileage driven: 69 Able-Bodied Questionnaire Name: Address: City: Phone: Sex: M or F (Please circle) Age: Years driving experience: Have you had high school driver education? yes no (Please circle) Have you had actual skid control training behind—the-wheel? yes no (Please circle) The state where you have done the majority of your driving: Number of reported accidents since you began driving: 0 l 2 3 4 5 or more Number of moving traffic violations since you began driving: 0 l 2 3 4 5 or more Estimate of annual mileage driven: APPENDIX C SKID CONTROL BRIEFING 70 71 SKID CONTROL BRIEFING Purpose You will be participating in a study to determine the level of driver skill in controlling a skid. The information that will be collected will illustrate performance levels of gpppp§_of persons rather than individuals. You need not be concerned about your indi- vidual performance being evaluated as "good" or "bad" since the infor- mation that will be collected has not been attempted before in any manner. It is hoped that your participation as part of a group will assist in answering questions in driver and traffic safety education. Skid Control Overview Skidding is a fact of driving--a fact that plays a significant role in traffic accidents. There are numerous types of skids that a driver will encounter. Although there is no absolute way to handle a particular skid, there are certain rules and techniques that can be applied to help control skidding. The basic rules are: 1. Do ppt_use the brakes until steering control is re-established; 2. 00 pp; use power (acceleration); and 3. Countersteer to correct for the skid. Countersteering, turning the steering wheel in the direction of the skid, is probably the most important corrective step that any- one can learn. Up to a certain point, a car can be kept under con- trol if you countersteer properly. But your reaction must be fast, smooth, and accurate. Let's look at a diagram that illustrates a vehicle traveling from left to right. 72 If the vehicle enters a skid and begins to rotate in the following sequence, a driver should begin to countersteer to the right since the rear of the vehicle is sliding right. Or to think of it in another sense, countersteering means steering in the direction you want to travel. In the same diagram you can see the direction the driver wants to travel is to the right, therefore requiring a steering input to the 1“!" ‘” “ “ H right. If the situation illustrated the rear of the vehicle sliding left, a steering input to the left would be needed. 73 Vehicle Reaction During your skid control participation, you may find your steering response to be incorrect or late and the vehicle will become uncontrolled. You don't have to worry about a vehicle rolling or flipping. In fact, a tire will not even be raised, although the move— ment inside the vehicle will be forceful. Therefore, as safety pro- cedures you are requested to 1. wear the lap and shoulder harness, 2. lock the door, and 3. obey instructions given to you by the in-car evaluator. You may also be able to control the vehicle, in which case the vehicle will stay in a fairly straight line. Often a secondary skid results; therefore, be alert to possible skids in the opposite direc- tion once you've controlled the initial skid. In-Car Instructions Before starting the evaluation, you will have an opportunity to drive the vehicle to become better acquainted with the vehicle handling characteristics such as braking, accelerating, and steering. The evaluator will direct you through a specific path once you are at the facility site. The maneuvers that you will participate in require 16 trials. Traffic cones will be placed on the facility to guide you into a starting position and into an entry position for the trials. The following is an overhead view that illustrates your paths of travel. (You will be alternating starting positions between A and B.) You 74 may apply full acceleration since the speed you can attain is deter- mined by the starting point and will be collected by radar. A A A / \ A A A /A IA 4‘ 48 A I D>/' D: A \ A A A A /. 71” 7» F—I 4 8 Once the vehicle is on the skid pan, you should release acceleration and concentrate on steering. Remember, your objective is to control your vehicle through countersteering once a skid has been detected! Please refer back to any section at this time if you have any questions. When you are finished, please indicate to the evaluator that you are ready for the in-car evaluation. APPENDIX D VEHICLE FAMILIARIZATION COURSE 75 76 R R B R v R A SKID PAN I i 260' I 1 H I I 1 >1 pom. “PF“ A LI=3EE§=35255225552531=§5334ALaa R A L L L B k) 1 1 710' _J I \ 4.x VEHICLE FAMILIARIZATION COURSE (not drawn to scale) 77 LEGEND: Designation No. in Predrive L Left Turn 5 R Right Turn 5 A Acceleration 3 B Braking 3 (Moderate to Heavy) APPENDIX E ABLE—BODIED AND PARAPLEGIC PERFORMANCE SHEETS 78 Name: 79 ABLE-BODIED PERFORMANCE Trial Number Initial Direction of Primary Skid L = Left R = Right Performance Level 0 = uncontrolled 1 = controlled 11 12 13 14 15 16 80 Name: Level of Lesion: PARAPLEGIC PERFORMANCE Initial Direction of Primary Skid Performance Level Trial Number L Left 0 uncontrolled R Right 1 controlled APPENDIX F SKID INDUCER 81 82 HYDRAM ITE HYDRAULIC 590 STROMBERG DOES NOT INTERFERE WITH CAR'S NORMAL BRAKE OPERATION. O i EflflEINDUGEB for Driver Training Cars Allows instructor to lock up one, Recommended for use by -’°" 0' Wk” WWW Professional Instructors in teaching controlled skid defensive driving and skid control ('Seurlie controls required For From A Back Din-es 1 HYDRAMITE IS THE PATENTED SYSTEM—Manuiacturec by the pioneers in the industry The name Hydramite has become synonymous with quality. reliability. and safety The Hydramite name is known and its products used through- out the United States and Canada by public. parochial and protessmnal schools for use on their driver training programs ,. . , .and endorsed by automobile clubs in support oi these , programs The Hydramite 590 Skid Inducer can be used in ~ COHIUHCIIOH with the Hydramite Dual Brake Control used in - these programs FITS MOST STANDARD US CARS regardless of year, make. or model. including cars equipped with any type 01 power brake Easily installed. easny removed when car is re‘ placed. wnhout detacmg interior of vehicle. Fittings and tubing Hya'ame Sm Induce, should be included eliminates need to our cars original brake lines NOTE' us sed ONLV by instiuctors with the proper training and Incmr ies' STROMBERG HYDRAMITE STROMBERG-HYDRAMITE CORP. 2626 W. Addison Street, Chicago. Illinois 60618 Phone 312/281-3000 APPENDIX G RIGHT-ANGLE HAND-CONTROL DEVICE 83 84 METHOD OF OPERATION The “Monarch Mark 1" incorporates the most popular method of operation and undoubtedly the least fatiguing possible. The brake is applied by pushing the control handle directly toward the brake. The accelerator is activated by moving the handle toward the seat, at right angle to the brake movement and parallel, or near parallel, to the rim of the steering wheel. The accelerator is generally applied for a far greater period of time than the brakes. many times for extended periods of several hours without the necessity of braking the vehicle. We believe this device incorpo- rates the most natural method of brake and accelerator movement possible and is almost a "must" for a quad- raplegic driver or person with severe hand and wrist weakness. Generally the weight of the driver's hand and arm is sufficient to maintain a desired speed. This de- sign allows the control handle to be positioned very near the steering wheel, if desired, to reduce the length of travel necessary to apply the brakes. Both the brakes and ac- celerator may be applied at the same time if necessary. This is desired by some persons and is sometimes helpful when starting or maneuvering on severe grades, and applying light brak- ing pressure to keep brakes dry when encountering heavy rain and high water conditions. Some persons unfamiliar with a control of this type may require addi- tional Ieaming and practice time. 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