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This is to certify that the
dissertation entitled

A SURVEY OF SOUTHWESTERN NEW HAMPSHIRE DRIVERS'
KNOWLEDGE OF SYMBOLIC SIGN MESSAGES

presented by

C. GEORGE BOWER

has been accepted towards fulfillment
of the requirements for

Ph. D. degree in EDUCATION

Major professor _.

Date NOVEMBER 4, 1985

 

MS U is an Affirmative Action/Equal Opportunity Institution 0-12771

 

 

 

MSU

LIBRARIES
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RETURNING MATERIALS:
Place in book drop to
remove this checkout from
your record. FINES will
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stamped below.

 

 

 

 

 

 

 

 

 

 

A SURVEY OF SOUTHWESTERN NEW HAMPSHIRE DRIVERS'

KNOWLEDGE OF SYMBOLIC SIGN MESSAGES

BY

C. George Bower

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

1985

Copyright by
C. George Bower

1985

ABSTRACT

A SURVEY OF SOUTHWESTERN NEW HAMPSHIRE DRIVERS'
KNOWLEDGE OF SYMBOLIC SIGN MESSAGES

BY

C. George Bower

Drivers' knowledge of symbolic sign messages that are
employed as traffic control devices has run: been reliably
assessed. Symbolic messages have seen increasing use in
recent years despite inconclusive evidence of driver
knowledge.

The principal objective of this study was t1) assess
driver's knowledge enui recognition <3f symbol signs.
Differences between groups (ME drivers, delineated tnr age,

sex, driving experience, and training, were studied through

the use* of a :fifteen item. domain referenced test. The
content validity of the instrument was set at r = .979 and
reliability vans set at r‘ = .9455. The test sample was

comprised of two hundred and twelve (212) drivers, selected
on the basis of license renewal date, from southwestern New
Hampshire.

The Pearson Product Moment and the Bi—Serial

correlation coefficients were employed to test association
between test \muiables. Intragroup differences were
measured using tflma t—test, ANOVA, time eta statistic, and
the test of linearity.

The study results showed a strong linear relationship
in the variable age, in that as age increased, symbol
knowledge decreased. A significant difference of 5.168
between the mean test scores of male (81.571%) and female
(76.404%) (drivers vuu; observed. Significant differences
were also found within the eight driving experience
classifications and a positive linear relationship was
established. in“; presence (ME driver education among test
subjects produced a mean score difference of +6.562. Sign
recognition and sign knowledge ‘were found to in; related

based on the obtained correlation coefficient of r = .739.

To my wife, Jackie

For accepting and sharing a goal
I have pursued;

for promoting this endeavor
when interest diminished; and,

for many hours of assistance
that is herein recognized.

ii

ACKNOWLDGMENTS

In the preparation of this report, I received the very
generous assistance of a group of people to whom I am
deeply indebted. A sincere note of appreciation is
extended to these individuals:

To Paul Paquereau, for his role in providing access
to SCSS and expert consultations on the data analysis and
computer generation of tables;

To Peter Salinger, for writing the data entry utility
and assisting with the data organization for SCSS analysis;

To time content ‘validity’ review team, consisting of
Fred Vanosdall, Dr. Paul Specht, Dr. Thomas Titzkowski, and
John Perroni, for their diligence in helping to validate
the test instrument;

To Zuni Clark, for lending her extensive Wang word
processing background to solving my technical printing and
formatting problems;

To the members of my doctoral committee, Dr. Peggy
Riethmiller, Dr. Joseph Dzenowagis, and Fred Vanosdall, for
their guidance and assistance in attaining this goal; and,

Without any hesitation, a very special
acknowledgement is due Dr. Donald Smith, who, as the
Chairman of my program, supplied the encouragement and
technical references that were essential to making this

doctoral program a meaningful developmental experience.

iii

TABLE OF CONTENTS

LIST OF TABLES . . . . . . . . . . . . . . . . . . vi
LIST OF APPENDICES . . . . . . . . . . . . . . . . vii
CHAPTER
I THE PROBLEM 1
Statement of the Problem 1
Background of the Study 1
Purpose of the Study 3
Significance of the Study 4
General Question to be Answered 6
Research Hypotheses 7
Basic Assumptions 8
Delimitations 8
Definition of Terms 9
Summary 10
II REVIEW OF LITERATURE 11
Historical Perspective . . . . . . . . . . 11
The Benefits of Symbol Signs . . . . . . . . 12
Effectiveness of Symbol Signs . . . 15
Perception and Recognition of Symbol Signs . 20
Drivers Knowledge of Symbol Signs . . . . . 24
Symbol Sign Testing Techniques . . . . . . . 29
Symbol Sign Design . . . . . . . . . . . . . 35
Summary . . . . . . . . . . . . . . . . . . 39
III DESIGN AND METHODOLOGY OF THE STUDY. . . . . . 41
Source of Data . . . . . . . . . . . . . . . 41
Sample Employed . . . . . . . . . . . . . . 42
Research Materials . . . . . . . . . . . . . 42
Procedure of the Study . . . . . . . . . . . 45
Research Design . . . . . . . . . . . . . . 47
Research Hypotheses . . . . . . . . . . . . 49

iv

Analysis of Data
Summary

IV ANALYSIS OF DATA

Demographic Information
Age and Sex

Driving Experience and Driver Education

Test Item Analysis
Crosstabulations and Intragroup. Statistics
Analysis of the Variable Age
Analysis of the Variable Sex
Analysis of the Variable Driving
Experience . . . . . . . . .
Analysis of the Variable Training
Summary

V SUMMARY, FINDINGS, CONCLUSIONS,
RECOMMENDATIONS AND DISCUSSION

Summary

Findings

Conclusions

Recommendations for .Further Research
Recommendations

Discussion

REFERENCES

APPENDICES

49
51

52

52
52
53
55
59
6O
63

64
67
69

71

71
72
75
76
77
77

83

87

Table

LIST OF TABLES

Age and Sex Distributions
Driving Experience and Training

Summary Table: Correct Response and
Recognition Rate for Test Items

Breakdown of Knowledge by Age Group

Summary of Statistical Analysis for the
Variable Age

T—Test Results for the Variable Sex

Cell Statistics for the Variable Driving
Experience . . . .

Summary of Statistical Analysis for the
Variable Driving Experience

T—Test Results for the Variable Driving
Experience

vi

Page
53

54

57

61

63

64

65

67

68

Appendix
Page
A.
B.
C.
D.
D1.
D2.
D3.
D4.
D5.
D6.
E.

LIST OF APPENDICES

Test Instrument and Answer Form

Validity and Reliability of the Test

Part I:
Part II:
Part III:

Instrument

Manual

Test Instrument Validity
Test Instrument Reliability
Content Validity Assessment

Readability Assessment of the Test Instrument

Analysis Tables of the Test Variables

Mean Scores of Test Subjects
and Sex .

Mean Scores of Test Subjects
and Training .

Mean Scores of Test Subjects
Driving Experience and Sex

Mean Scores of Test Subjects

by Age
by Age
by

by

Driving Experience and Training

Mean Scores of Test Subjects
and Training

by Sex

Correlation Matrix for Test variables

Breakdown of Test Item Responses

El.
E2.
E3.
E4.
E5.
E6.
E7.
E8.

Item 1: No Left Turn

Item 2: Right Turn Only

Item 3: Keep Left

Item 4: Do Not Enter .

Item 5: Center Lane Left Turn Only
Item 6: Right Curve .
Item 7: T— Intersection.

Item 8: Merging Traffic

87

92

93
95

96

126

128

129

I30

131

132

I33
134

I35

136
137
138
139
I40
141
I42
143

 

E9.

E10.
E11.
E12.

E13.
E14.
E15.

Item
Item
Item
Item

Item
Item
Item

9:

10:
11:
12:

13:
14:
15:

Merge Left . . . . .

Divided Highway Ahead

Slippery Road . . .

Low Clearance — 12 Feet
6 Inches

Narrow Bridge

Workers On Road

Two Way Traffic

viii

144
145
146

147
148
149
150

 

CHAPTER I

THE PROBLEM

Statement of the Problem

 

The problem addressed in this research was the
assessment of drivers' knowledge of selected traffic symbol
signs. A test was administered in December 1982 to
southwestern New Hampshire drivers during the license
renewal process. The study was intended to discern
differences between groups of drivers, which were based on
age, sex, training and driving experience, and their

knowledge of the selected symbol signs.

Background of the Study

 

One (M5 the primary controllable nmdes (ME information
presented to drivers in the traffic environment is traffic
signs. Messages on signs are essentially presented 1J1 two
types: word and symbolic messages. The driving task
involves tine driver's ability tx) interpret tflue meaning (of
signs accurately' under 51 wide variety (of conditions and
often with specific time limitations.

Symbol signs have been used as traffic control devices
on the highways of this country almost since the invention
of the automobile. In order to develop a Inore uniform
motorist communication system, time federal government
decided in the early 1970's to adopt some of the

international symbol signs. Since then, symbol signs

 

have been demonstrated to be an effective form of
communication with drivers in this country and 111 foreign
countries. (1,8,14)

More than one hundred symbol signs have been accepted
by the federal government for use on streets and highways.
The major categories consist of regulatory, warning, guide,
information and construction signs. There has been
extensive use of symbol and pictographic signs in the
traffic system. in“; greatest demand exists in the
recreational and service sectors and can be seen widely in
roadside advertising.

An interest 111 tourism anui education. in tflma United
States, by foreign individuals, along with the growth of a
multilingual population, creates a need for symbol signs in
the transportation system. In some sections of the
country, English has become the second language.

The science (ME symbol sign development involves very
complex perceptual considerations that have been researched
both here anui abroad. Symbols Ck) not necessarily change
the content of a sign, but there is still difficulty in
expressing content through symbols. The word message "road
narrows" and the symbolic message are both intended to
cover the same condition, but communicating the information
so that there is a singular interpretation is difficult.

Relatively little research has been conducted to

determine drivers' knowledge of the symbol signs since

their implementation, and no assessment has been made

previously in the State of New Hampshire.

Purpose of the Study

 

Symbol signs and signs in general are intended to
provide drivers information about roadway and traffic
conditions in order to improve both safety and efficiency.
The extent to which symbol signs accomplish this objective,
and to which drivers understand the messages presented by
the symbols, has not been adequately documented. The
purpose of this study was to assess drivers' knowledge of
selected symbol signs that are used as traffic control
devices. A secondary purpose of the research was to
determine drivers' familiarity with the selected signs.

This study was directed at identifying the symbol
signs essential to the driving task that are most
recognizable and those that are least recognizable. The
audience(s) most affected by misinformation was also
studied.

Public information accompanying the development and
use of symbol signs has been limited at best. Symbol signs
are generally considered to be self—evident and appear
without word messages. Whether the signs are learned
through trial and error or are self-explanatory" is not
Clear. Driving experience was correlated with sign

knowledge to obtain a partial answer to this questions.

The study was designed to answer the research
questions relative to a selected group of symbol signs
deemed most critical to the driving task by traffic
experts. No attempt was made to determine drivers'

knowledge of all symbol signs.

Significance of the Study

 

Since the institution of the system of symbol signs,
little research emphasis has been placed on determining
drivers' knowledge of these signs. Previous research
(1,14) has centered on gathering information on symbology
and the science of symbols. The characteristics of
symbols, the attention demanded, and the message conveyed
by abstract forms have received considerable attention from
both the traffic and psychological research communities.
(14,19)

Drivers rely almost entirely on information received
from the traffic environment in performing the driving
task. Processing the information accurately and rapidly is
dependent, in part, on the quality and the fornl of the
stimuli presented. Symbol signs are used to communicate
messages in such a mode as only to require recognition and
interpretation of the sign content without the need to
comprehend and interpret the meaning of word messages. (1)

The study also intended to identify the groups, based
on the study variables of age, sex, driving experience and

training, in which symbol sign knowledge needs the most

 

improvement. Previous research has indicated deficiencies

in certain age classifications of drivers. (1,2,5)

Large amounts of money are spent by the State of New
Hampshire each year on the installation and maintenance of
signs about which little is known regarding drivers' use
and understanding. While previous research has employed
laboratory techniques and intact groups, this effort
tested a random sample of drivers using a valid and
reliable test instrument.

The study provided information that can be applied to
the transportation system to affect cost and efficiency.
Cost is a factor in as much as some signs may be
unnecessary or inappropriate for their purpose.
Efficiency is considered from the standpoint of
communicating a message in a clear and singular fashion.
Public dissatisfaction with the traffic control devices
used in the traffic system is voiced almost daily through
the media and to governmental officials. (2) Traffic
signs that do not convey the proper information or present
inaccurate or easily misinterpreted information, are
common on the highways.

An attempt was made to evaluate the input function of
the driving task for the driver as an information
processor. By comparison, output in the driving task is
far simpler to measure than input. Information density
and information processing capabilities are determining

factors in the reception of stimuli from the environment

(13). The process of discrimination and the ability of
the driver to discriminate affect input and the overall
performance of the driving task. (13) The relationship
of symbol sign research to this issue involves the ability
of the driver to process information accurately and
rapidly' and. the determination of the signs anui symbols
that effectively discriminate in presenting messages.
Signs should discriminate in terms of form, content, and
intensity. This study was intended to identify the signs
of major importance and their ability to project a
discriminating or singular message.

Recognition and understanding received emphasis in
the study rather than the concepts of detection and
identification. By assessing recognition and
understanding, the question of what the information

presented on the sign meant to the driving task was sought.

General Questions to be Answered

 

The major research questions answered by this study

are as follows:

1. Do drivers in southwestern New Hampshire
understand the meaning of selected symbol signs?
2. Are the variables of age, sex, driving
experience, and formal training factors
affecting drivers' understanding of symbol signs?

3. Have drivers seen or are they familiar with the

selected symbol signs in the traffic environment?
Are certain selected symbol signs better
recognized and understood by drivers than other

symbol signs?

Researchgfiypotheses

 

The null hypotheses tested in this research were:

H01:

H02:

H03:

H04:

The

was set at

There is rm) significant difference between Inale
and female drivers' knowledge of symbol signs.
fill-#2 = 0
There is ru> significant difference in 'the
knowledge of symbol signs between drivers with
formal training and those without formal training
in the driving task.
11—11. = 0
There is I“) significant difference 111 the
knowledge CHE symbol signs between the age
classifications of drivers.
#1-#2-#3-#4-#s-#e-#7= 0
There is IN) significant difference in the
knowledge of symbol signs between the experience

classifications of drivers.

ux-uz-uz-m-ks—m-uv—Afi 0

level (ME significance for 5H4. statistical tests

.10.

 

Basic Assumptions

 

Four assumptions were made in conducting this

research:

1. The content validity and reliability of the test
instrument, established as part of the research,
were sufficient for the purposes of this study.

2. Individual responses of the test subjects were
based on true symbol sign knowledge.

3. Symbol sign knowledge can be tested through the
use of a valid and reliable test instrument.

4. Expressed opinions are held opinions.

Delimitations

For the purposes of this study, the following

delimitations were established:

1. New Hampshire residents are eligible to obtain a
drivers license at age 16 with the renewal
required at three year intervals. Age groupings
were set at 16—19, 20—29, 30—39, 40—49, 50—59,
60—69, and 70 and older.

2. The symbol test was administered to drivers who
were scheduled for renewals during the month of
December in 1982.

3. Only drivers from southwestern New Hampshire
were tested as a part of this study. New
license and out of state transfer applicants

were not tested.

Definition of Terms

 

SYMBOL SIGNS: The internationally accepted
emblem and picture signs, without accompanying
words, used to provide information to drivers.
DRIVING EXPERIENCE: For the purposes of this
study, a value representing the number of mules
driven by a driver in a period of one week.
FORMAL TRAINING: The completion of a formal
driver education course as a prerequisite to
licensing.

WORD MESSAGES: The statement or legend
accompanying a symbol sign to provide the driver
a second source (HE information about the sign.
(9)

KNOWLEDGE: The driver's understanding,
awareness, and comprehension of the symbol sign
message.

FAMILIARITY: The fact of whether or not a
driver has seen or recognized a symbol sign.
DOMAIN—REFERENCED TEST: A test instrument using
a sample of questions to evaluate a body of
knowledge.

DIAGRAMATIC SIGN: A sign using symbolic
messages to indicate a path of travel on a
highway. (14)

DISCRIMINATION: "Hue ability t1) distinguish

between confusing (n: ambiguous stimuli from the

10

driving environment; the presentation of a
singular message by a symbol. (14)

10. DETECTION: The perceptual act of seeing a
symbol sign in the traffic environment.

11. IDENTIFICATION: The act of being able to
accurately name the symbol sign seen in the
traffic environment.

12. RECOGNITION: The act of being able to interpret
the meaning of the message of a symbol Sign seen
in the traffic environment.

13. VISUAL CUES: The elements of color, contrast,
motion, intensity, enui positirnh that serve as
visual stimuli in the traffic environment.

14. PICTOGRAPHIC SIGNS: Signs employing picture

symbols as opposed to abstract symbols to

communicate a message. (16)
§EEEEEY
In the preceding discussion, a. need inns been

indicated for symbol sign research and for the
investigation (M5 the» relationship between. the test
variables and symbol sign knowledge.

Chapter Two of this report presents findings of
previous sign research that was applicable to this study.
The relationship between sign messages and the driving

task is defined as well as related research methodologies.

 

CHAPTER II

REVIEW OF LITERATURE

Introduction

The majority of the research conducted in relation to
symbol signs has focused on the individual characteristics
of the signs such as legibility distance, attention value,
and understanding of the message symbol. No comprehensive
study has been found to date that deals with all the
essential tasks of detecting, recognizing, and acting on a
wide variety of symbol signs, using a true random sample of

the driving population.

Historical Perspective

 

In 1949 the United Nations Protocol for Standardized
Signs was adopted in an attempt to bring a degree of
uniformity to the international motorists' communications
networks. It was not until 1962, through the work of
several Japanese citizens, that the International Committee
for Breaking the Language Barrier was established in New
York. This organization proposed the adoption of symbols
as an international traffic communication medium and
actively lobbied for implementation.

The 1962 United Nations Conference on Road Signs
produced a rudimentary guide for international signs but
not all were symbolic in nature. Relatively few countries

participated in the development of the sign proposal and

11

12

thus, it received only modest support. (13)

In preparation for the 1964 Olympics, the Japanese
government became the first to adopt symbol signs in a
uniform manner. (It is interesting to note that both the
Chinese and the Japanese alphabets are derived from
symbolic representations for use as characters.) Soon
after, the United Kingdom and the Canadian province of
Quebec instituted symbol sign systems for their highways.
(10)

Not until 1971 did the United States government adopt
a limited number of symbol signs for use on highways. A
year earlier, the U.S. Park Service implemented a system of
symbol signs in parks and other recreational areas in order
to better accommodate foreign visitors. Since the
mid—1970's, the United States has devised a system of
symbol signs for highway communications and provided for
extensive implementation. However, this system is; not in
full accord with the standardized internationally accepted

symbols. (13)

The Benefits of Symbol Signs

 

The benefits of signs employing symbols to communicate
messages (symbol, diagrammatic, and changeable message
signs) have not been clearly defined in sign research.
Mast and Kolsrud (14) conducted. a study that indicated
diagrammatic signs produce tangible benefits in sizable
reductions in hazardous inaneuvers, improved lane

positioning, and in reduced indecision at gore areas.

13

Their field study suggested that the greatest benefits are
derived in areas where unexpected or unusual maneuvers are
common.

Multiple message displays incorporating symbols can
address a broader range of traffic management problems and
roadway and environmental conditions, according to the
research findings of Allen, et a1. (1). These signs also
have the advantage of being able to inform drivers of the
type of action(s) required for a given situation with
specific information.

Symbols convey information in much the same way as
conventional signs except that no reading skills are
utilized in the communication process. The accuracy of
well designed symbols in conveying an intended message is
very high. Not only can a symbol be used to present a
condition or situation with one statement but the degree
and intensity can also be communicated to the audience. (4)

For example, Roberts (17) found that diagrammatic
signs more adequately communicate the driver's position
relative to an exit within an interchange than conventional
signs. An advantage is gained by having the operator
visualize the approach to the interchange prior to entering
the area where decisions are demanded. The decisions on
position and direction are then mentally stored and the
task becomes one of updating and executing the decisions.

Drory and Shinar (6) described several drawbacks of

symbols used as communication devices. The foremost

 

 

14

problem was that as the graphic component(s) of the sign
became more complicated, the time required by the driver to
interpret the information increased. Drivers also need
additional time to read and interpret the information
displayed on complex diagrammatic signs in comparison to
conventional signs. Intricate graphics increase the
information content in the sign message but at the same
time place increased processing demands on the vehicle
operator.

Allen (1) found that some diagrammatic and symbol
signs may actually enhance the problems drivers encounter
at interchanges with single right exits, common Cloverleaf,
and very complex interchanges by producing indecision.
This situation leads to two general recommendations
regarding the use of symbols. First, simple graphic
designs must be employed whether the message is complex or
elementary. Sensory overloads are as much a consideration
in signs as in roadway design. The second recommendation,
involving response time, remains an essential consideration
even though the information content of the sign is
heightened by a symbol without additional verbage. A major
variable is the processing and execution time needed after
the sign has been observed and the information content
transmitted to the driver. (1)

The Transportation Research Board (TRB) (18)
determined that cost tends to be a factor in favor of

symbol signs; especially in comparison with the application

15

of diagrammatic and changeable message signs. Special
symbols and legends demand individualized construction at
additional cost. Maintenance and installation costs are
much higher for the diagrammatic and changeable message
signs than for mass produced conventional signs.

Most benefits are derived from the ability of the
symbolic representations to transmit simple and meaningful
messages without the use of lengthy legends, according to
Allen.(l) The integrity and density of the information
content presents both positive and negative results
depending upon the specific application. The function of
the symbol sign is limited though by the variable abilities
of vehicle operators who have widely divergent capabilities
in perceiving, processing, and acting on the information

transmitted. (1)

Effectiveness of Symbol Signs

 

Most research supports the superior performance of
symbol signs in communicating messages as compared to
conventional signs. Diagrammatic signs, changeable message
signs, and symbol signs are more effective in most
situations requiring special or detailed applications due
to the specialized design to fit the demands. As described
earlier, the information content of the symbol is greater
and requires significantly less reading and response time
than conventional signs. The effectiveness of symbol signs

is directly related to the attention value of the design

16

and this element may, in fact, be the key to transmission
of information. (6,14,18) Allen (1) demonstrated that
symbol signs provide legibility as good as, and in many
cases better than, conventional word message signs.

In the same study, Allen (1) investigated the
influence of the geometric complexity of the graphics in
establishing inherent meaning. He found that increasing
time geometric: complexity tended. to make the symbol more
obvious. Symbols with inherent meaning were more easily

recognizable and may be immediately familiar to the driver

upon initial exposure. Complex graphics make the symbol
distinctive and isolate its meaning from outside
interference. Singular meaning is essential to a symbol

anui when. attained, the application was limited to those
situations and demands most appropriate to the design.

Allen (1) also compared the single symbol to 23 single
word employed on a sign. The two were equivalent and
required a little over two seconds for reading and
comprehension by the driver. This fixation was relatively
long when combined with other driving tasks. Warning
signs, according t1) Drory and Shinar (6), receive shorter
fixations than directional signs. Most snmfixfl. signs fall
into time warning classification which may account for the
shorter fixations. The symbols used in vnnnmjm; signs are
generally simple in both content and context. The
directional signs employ rmnxa graphically complex symbols

and word messages by necessity in order to communicate

 

17

sufficient information to guide motorists.

When signs have the capacity to present multiple
messages using several symbols or words, TRB (18) findings
define the advantages over single message signs. Single
message signs are appropriate only when the situation is
recurrent and the same driver response is solicited each
time the sign is encountered. They are applicable for only
the intended purpose and the accuracy and credibility of
the sign.:hs questionable over time. The nmltiple message
signs can alert drivers to a broad range of problems
without presenting unnecessary distractors.

TRB research findings indicated that reading and
comprehension should increase for multiple message signs if
simply the bulk and complexity of the information displayed
is considered. Longer scanning and fixation times are also
implied. At issue is whether or not the multiple message
sign improves the quality of the information reception
process while increasing the fixation times. While the
process (ME percepticni is questionable, tflua fact that the
multiple message sign improves the attention (n? the driver
by providing variable information is aa decided advantage.
(18)

Legibility, recognition time and efficiency in
presenting the sign message are the most obvious benefits
of symbolic messages. When the complexity of the symbol is
sufficient to increase the reading and comprehension times

this element becomes 23 detriment unless adequate response

18

time is allocated to the driver in each application. (18)

Roberts (11) defined the attention value of
diagrammatic guide signs as seeming to be greater than that
of conventional signs, which is probably due to the
increased size of the legend. The symbols used on
diagrammatic guide signs presented a more formidable
character for viewing than conventional word messages. An
essential element of any sign, symbol signs included, was
the attention value inherent to the design. Attention
value was the degree to which the sign components
collectively demanded observation or review by the driver.

The yellow/black warning signs were described by Allen
(1) as having the highest attention value of all signs
while the white on green service signs have the second best
recognition. Although the white on green had high
attention values, it also produced some of the highest
rates of recognition errors. Allen cited geometric
complexity of the symbol as a second crucial factor, but it
also produced other perceptual elements influencing driver
recognition and behavior, as described earlier. Attention
value was determined by visual cues such as color,
contrast, motion, intensity, position, size, repetition,
and shape. These factors caused drivers to visually divert
attention from one orientation to another.

Communicability of information to drivers is the basic
requirement of all signs. Roberts (17) studied the

communicability of symbolic messages and discovered that

 

“Ar——
19

they more clearly presented information relative to exit
directions at advanced locations than did conventional
signs. Mast and Kolsrud (l4) corroborated this finding in
research showing that diagrammatic signs produced the
greatest benefits where unexpected or unusual maneuvers can
be anticipated. The diagrams of the exit areas, lanes and
routes clearly defined driver choices and removed from the
driving task the necessity to read and respond to lengthy
word messages within a short time span.

Multiple message signs can address a broader range of
traffic, roadway, and environmental situations, according
to research by the TRB (18). These signs are most
effective in alerting drivers to the conditions they are to
encounter and in informing them of the appropriate actions
required in the specific situation.

In conducting a study on the effectiveness of
changeable message signs, the TRB (18) found that the
efficiency of regulatory, advisory, and warning signs, was
nearly impossible to quantify because of the factors
producing bias in the study. The difficulty was in
determining whether the test sign or a later relevant cue
affected driving behavior. As the efficiency of the
symbolic message improves, the demand placed on the driver
increases while the time required for recognition
decreases. Symbol signs are not appropriate in every
situation as some very complex conditions are virtually

impossible to represent accurately with simple graphics.

I!)

20

The TRB study did determine that the changeable
message sign was a step up from the conventional symbol
signs with regard to attention value. Problems existed
however, with fully reliable data that would allow the
researchers to quantify the difference. The greatest value
of the changeable message signs was in communicating
information under adverse weather and roadway conditions.

The requirements for traffic control devices defined

in the Manual on Uniform Traffic Control Devices for

 

Streets and Highways (16) are all essential in insuring the

 

effectiveness of signs. The effectiveness of sign messages
is dependent upon proper application of the sign, attention
value of the graphics, selective or limited use, and a

clearly recognizable message.

Perception and Recognition of Symbol Signs

 

Drory enui Shinar (6) asserted that traffic control
devices are lfififli to inforni drivers about something that
the roadway (n: the environment does run: or cannot inform
them. Signs provide response time to situations that are
not known to time driver. Markowitz, Lees, 6%: al., (13)
defined a classification (ME probability' signs or those
intended to inform the driver of sxnme condition cm: hazard
that rmnr exist in the traffic environment. The driver's
response was determined by the probability that the
condition(s) described by the sign exists in the

environment. Past experiences enui environmental stimulus

21

were evaluated to assess the potential of the hazard or
condition being present.

Earlier discussion by Allen (1) noted that the
attention value of a symbol is a dominant factor in driver
recognition and understanding. Drory and Shinar's (6)

research into the attention value of signs also defined

several principles (ME driver attention. They tinnui that
as the demands of the driving task increase, the
individual differences between drivers, i.e. fatigue,

emotional state, etc., are reduced as more mental capacity
is required. When the situations presented in the driving
environment are less demanding, the individual differences
become rmnma pronounced. Fatigue (uni be suppressed
temporarily ii? the attention demanded of the driver is at
a high level, but as the demands diminish, the driver may
relax to the point of being inattentive.

Drory and Shinar (6) stated that the upper limit of
sign recognition is determined by attention. The
attention value of the sign and the attention of the
driver to line driving task anxe both relevant. When the
driving task (Lanands attention, such as vnlfli a winding
road, attention increases and 5%) does sfirni recognition.
Their research used road design factors as a study
variable.

A 1969 study of symbol recognition, conducted in
Ottowa, Canada, by McLean (15), used a questionnaire to

test eight sign symbols. The symbols selected tin: study

22

were: No Parking, No Stopping, One Iknu: Parking, Pavement
Narrows, Bump, Construction Flagman, Slippery Road Ahead,
and One Lane Traffic. Three of the symbols exhibited a
high degree of recognition: the "P" 1mmmi as a substitute
for the word "parking," Flagman Ahead, and Slippery Road
Ahead. The research report specified neither the criteria
employed to define a high degree of recognition nor the
symbol sign selection criteria.

Gordon (8) conducted research on the subject using
diagrammatic and conventional signs. While (diagrammatic

and symbol signs are rmfl: equivalent, time design concepts

(avoiding word messages) are the same. In six of the ten
locations studied, reaction time for the diagrammatic
signs was shorter. Two of the locations reached

significance at the .05 level using a t—test for corrected
measures where N=30. The test measures were based on the
speed and accuracy of the subjects lane changes as
determined by observers. Reaction time demanded
recognition on the part of the driver. Some of the
diagrammatic signs were more suitable and effective for
particular interchange designs. Conventional signs did
produce fewer lane placement and selection errors.

Gordon's findings support the assertions made in
other research that symbols and diagrams are more
effective in lrwv task load situations inn: that the value
of the signs begins to decline as the complexity of the

tasks increase. The research on sign recognition does not

23

clarify the apparent contradiction between. the improved
response time produced through the use of symbols and the
degradation (if responses anmi maneuvers when symbols are
employed in complex situations. The fact that the
subjects in Gordon's study expressed a personal preference
for conventional signs may tme indicative of driver

acceptance (if the symbols that the not appear as

"friendly." Other research cited previously described the
difficulty of expressing complex situations with
graphics. Recognition is improved when the route and

destination information. is matched with the major
diagrammatic components of time sign, according to Roberts
(17). The components of time sign allow time driver ti) be
more discriminating when making lane selection and travel
directicni decisions. Graphic and situational complexity
tend to be less problematic in the presence of adequate
discriminating symbol qualities.

Markowitz, Lees, et a1. (13), determined. that the
shape of the sign has rm) inherent meaning ti) drivers and
that it: is probably time least important design element.
But since shape is; helpful tin: sign recognition iii some
cases (stop, yield and other singular purpose shapes), the
effect on recognition must be considered.

The research of Mackie (12), Dewar (4), Roberts (17),
Drory and Shinar (6), and others depended upon recall of
signs when driving. The classic experiment asked the

subject to specify a sign that had been passed when

24

stopped after travelling through a test area. Drory and
Shinar (6) claimed that recall is related to attentional
and. motivational factors rather than those of memory' or
sensory inputs. There was a failure to account for the
process and effect of discrimination as a perceptual

consideration in these studies.

Drivers' Knowledge of Symbol Signs

 

Kato (11) proposed ten criteria for the development
of symbol signs with universality. These recommendations
serve as some of the primary test criteria in the design

of symbolic messages.

1. Is it easy to associate the symbol with its
message?
2. Does the symbol fit different cultures and

different local situations?

3. Does the symbol fit the changing times?

4. Is the symbol pleasing and acceptable without
controversy?

5. Does the symbol conform with existing
international symbols or other elements?

6. Is the symbol or its element capable of
systematic application for a variety of
interrelated concepts?

7. Is the symbol easily reproducible? Is it
applicable for many different purposes?

8. Is the symbol distinguishable from other symbols?

25

9. Can the sign be perceived from different angles
and perspectives, under different light
conditions?

10. Can the symbol withstand vandalism and
contamination?

In a) 1966 study' entitled Progress in Learning the

 

Meaning of Symbolic Traffic Signs, (12) Mackie

 

administered a questionnaire to 476 drivers to test their
knowledge of symbolic traffic signs. The instrument was
designed to collect data relative ti) the understanding of
the shapes, colors, and meanings of the signs. The
variables consisted of age, sex, social class, geographic
area, and experience driving outside of the country. A
secondary area of concern centered on the method of
learning the meaning of the symbol signs.

When compared ti) a similar test conducted 111 1965,
Mackie observed significant differences in several areas.
The mean value of knowledge on identical test items
improved 16% in the latter study' (P (.001). While the
percentage of correct answers increased, the percentage of
incorrect answers remained tmonstant. The (jifference twas
accounted for through a reduction in the rmana: of partly
correct responses.

The most widely recognized symbol sign was the
Advanced Warning — Traffic Signal Ahead sign, which had
almost universal recognition. The least recognized symbol

sign was the Parking Regulation grouping.

26

Two important factors identified in the research are
that seeing the sign while driving was an indicator of
drivers' knowledge of the symbol signs, but not the
complete answer, and that the most common method of
learning signs was self reported to be guessing.

There twas EH1 inconsistent level of knowledge among
the groups of British drivers on the various symbol
signs. No significant differences were reported between
male and female drivers but there were significant
variations between knowledge and age. The drivers who
knew the principles of the sign classification system (3%
of the population) gave significantly' more correct
responses than drivers who did not know the classification
system. (12)

Similar findings were reported by Dewar and Swandon
(5) in a 1971 report. They found 1m) significant
differences iii Canadian cjrivers vdiii regard ti) sex, but
again established a significantly lower level of knowledge
among older drivers; especially those over 6%) years <of
age. Driver education was identified as having a possible
enhancing effect on knowledge of certain classes of signs,
but not all.

Their research produced evidence suggesting that
older drivers take longer to process sign information and

have less knowledge of signs in general. The testing

27

revealed that response distance decreased with age for
several reasons:

1. poorer dynamic visual acuity;

2. greater time required for perception,
recognition and response due to increased
processing time; and,

3. unfamiliar settings.

Important implications are seen in the above elements
when considering sign placement and educational programs
with respect to populations over sixty years of age.

Dewar and Swanson (5) determined that "the evidence
comparing symbols with word messages in traffic control
signs is inconclusive and insufficient." A major
inconsistency exists in the design of symbolic messages in
that some represent hazards and others represent risks.
Whether the sign issues a positive or negative connotation
(a do or do not command) was also identified as an area of
conflict.

These researchers have defined the most important
design and test criteria in terms of what action the
driver will take in response to the symbolic message. In
related work, Dewar (4) determined that symbol signs
provided legibility as good as, and in many cases superior
to, word messages. The symbols were the equivalent of
single words and as such, required a little over two
seconds for reading and comprehension while providing

needed information.

28

An early study by Janda and Volk (10) found that
directional control was best provided by an arrow (i.e.
symbol) alone. The effectiveness of sign messages was
defined from highest to lowest as symbol alone, to symbol
and words, to words alone.

Additional research involving symbol signs was
conducted by the American Automobile Association's (AAA)
Foundation for Traffic Safety. (2) In a 1980 study

entitled Motorists Understanding of Traffic Control

 

Devices, Test II, a research test film was used to

 

evaluate drivers' understanding of traffic control devices
in traffic situations. Nineteen traffic situations were
used to test signs, signals, and markings. A nationwide
sample of 1700 drivers from civic, fraternal, and other
intact groups participated in the study.

AAA also found a wide variance in the understanding
of traffic control devices, which encompasses pavement
markings and traffic signals in addition to signs. There
was no significant difference between the male and female
drivers tested but older drivers' knowledge tested. at a
level significantly below that of younger drivers. The
study determined that symbol signs were better understood
than either traffic signals or pavement markings. The
highest level of performance was established when testing
the Railroad Crossing, the Advance Warning — Stop, and the
Advance Warning — Yield signs. Poor performance was

exhibited on the Exit Only and standard Yield signs, while

29

the Continuous Lane and the No Merge Required signs
produced the lowest levels of performance.

A field study by Drory and Shinar (6) demonstrated
that only six percent of drivers questioned could recall
the study sign after driving past the test site and that
nine percent could recognize the sign when pictured on a
sheet depicting warning signs. The researchers cited
factors of fatigue, size of the vehicle, absence of
passengers and sex as determinants in recognition. The
measure used to determine fatigue produced (a correlation
of .62 in predicting sign recall.

The types of training employed by both Mackie (12)
and Dewar (4) in their research showed no appreciable
influence in enhancing test subject scores. Dewar used
pamphlets, educational plaques and combined the techniques
without significant results. While age has been shown to
be a factor in initial testing of knowledge, all age
groups learned an approximately equal number of signs
during the symbol sign training sessions conducted by

Dewar as a treatment after pre—testing.

Symbol Sign Testing Techniques

 

Test and population variables were relatively
consistent among the studies reviewed in this literature
search. Mackie (12) tested knowledge of symbol signs over
the widest range of variables. He included social class,

age, sex, driving experience outside of the country, and

30

area (ME residence for time British subjects. Several of
the classifications contained small groups of subjects,
especially in the older populations, and the analysis was
limited. AAA. (2) used. the 'variables of age, sex, and
region of the country for a test of 1700 UJS. drivers in
1980 while Allen et a1. (1) tested drivers on the basis of
age, sex and training.

Age was the one variable showing the greatest

differences lfl almost EHJ. research. Allen, et en” (1),
Mackie (din, Dewar (4), and AAA (2) drew similar
conclusions from their tests. In general, sign knowledge
decreased vfiiii age. Older drivers' performances were the

worst on regulatory symbol signs and were particularly bad
on prohibitory signs. Allen suggested that since the
regulatory signs contain a large number of directional
signs with similar or related meaning and symbols, they
create confusion for older drivers and require longer
perception and reaction times. The only variable
consistently showing no significant differences was sex.

Most CHE the testing has avoided any task loading and
utilized static rather than dynamic presentation. Notable
exceptions are the studies by AAA (2), which used
simulation,and the field studies by Markowitz (l3), Drory
and Shinar (6), and Mast and Kolsrud (14).

Test procedures covered.ee wide variety (Hf techniques
in both the field and laboratory research. Testing has

been conducted using questionnaires, simulation and films,

31

mechanical testing, and field observations and tests.

Drory and Shinar (6) stopped vehicles 200 meters
beyond a sign in a test in their field studies, but
limited their analysis to only passenger vehicle
occupants. Time selection of time vehicles was rmm: random
as platoons of vehicles were not stopped and vehicles were
permitted to pass if there was the potential to inhibit
the free flow of traffic. Other field studies used
observers or mechanical testing and recording units to
analyze drivers' responses to signs.

Dewar and Swanson (5) conducted laboratory tests of
drivers' knowledge of symbol signs in Canada. City
employees and driver education students were introduced to
all test signs and given the meaning prior to the test to
insure timi: all symbol signs were familiar. The testing
consisted of showing a slide projection of the sign in the
traffic environment and the subjects were required to
write the appropriate driving action on the answer sheet.
Mackie (12) anmi AAA (2) employed paper and pencil testing
and driving simulation respectively. AAA produced a
special test fihn of' nineteen. traffic sflinm signal, and
marking situations. A questionnaire, corresponding to the
fihn, was used ti) record time subjects' responses to the
traffic situations.

Allen (1) and AAA incorporated aspects of training
into the testing process. Allen applied three treatments

to subjects consisting (if signs and educational plaques,

 

32

pamphlets explaining the signs, and a combination of the
two techniques. No significant differences were found on
the effects of knowledge. AAA provided feedback to the
test subjects by means of a specially treated
questionnaire that would reveal the correct answer when a
chemical marker was used to color the answer circle. If

the correct circle was colored, the work "ok" would appear.

Markowitz, Lees, et a1. (13) were the only
researchers to deviate from the correct/incorrect
designations for responses. They utilized strictly

correct, generally correct, irrelevant, and contradictory,
in assessing drivers' actions when approaching complex
interchanges in a field study. The other research
involved the selection of the appropriate response or
classification, as in the case of a questionnaire. Few of
the questionnaires allowed open—ended responses i.e., no
answers were presented and the subjects were required to
write a response. Dewar (4) did not report any difficulty
with this methodology' but an unpublished study by Emery
(7) found that drivers could not formulate responses.

Field testing and laboratory testing of symbol signs

necessitates the application of different techniques and

purposes. McLean (15) devised a field test with a test
construction site to evaluate drivers' responses to
construction zone signing. Driver actions were recorded

on video tape and a questionnaire was administered after

passing through the area. Dewar (4) cited significant

 

33

problems with field studies in that a strict set of common
operational definitions is not available for such terms as
conflict, erratic maneuver, lane selection error, etc.
Not only is it difficult to measure these variables but
replicating the research is impossible. Driver feedback
is also a limiting factor.

The value of field studies is that an indication of
drivers' response to a symbol sign can be observed in some
situations. Also, true environmental conditions are
incorporated in the studies and task—loading is present.

Laboratory studies, on the other hand, have four
major short—falls, according to Dewar (4). The test item
presentation is usually not in random order and random
selection of subjects has been difficult to obtain.
Laboratory studies also lack normal visual cues and
distractions found in the driving environment and static
testing tends to be a draw—back as the reaction and
decision time factors are often eliminated.

Symbol sign experiments generally measured only one
factor in the complex process of sign perception,
recognition, and volition. As stated earlier, the
majority of all sign research has centered on legibility
and visibility. The ability of the symbol sign to
communicate a message is well defined. Dewar (4) suggests
that the most important aspect of symbol sign testing
should be the ease with which the sign can be learned and

remembered.

34

Several studies were designed to evaluate a single
sign or a group of signs and, as such, selection criteria
are not applicable. AAA (2), Mackie (12), and Dewar (4)
neglected to provide any rationale for the selection of
symbol signs to be tested.

Allen, et al., (1) provides the most comprehensive
assessment in this regard in establishing a goal of
developing a balanced presentation of symbol signs. The
primary criteria considered were:

1. Levels of semantic complexity; and,

2. Different types and colors of signs.

Twelve signs from each of the six categories of

signs, as defined in the Manual on Uniform Traffic Control

 

Devices for Streets and Highways, were included.

 

After ranking the signs in the group for complexity

within the group, Allen's selection was based on:

1. Universality of usage;

2. Availability of good quality art work;
3. Minimal redundancy; and,

4. High semantic or geometric complexity.

Each of the categories included signs of different
shapes, colors, and contrast conditions. Several complex
signs were selected for high semantic and/or geometric
complexity that would not otherwise have been included in
the groups. Emery (7) selected signs that were listed in
the State Drivers' Manual (Michigan) and those that were

new or had changed color.

 

35

Dewar (4) contended that the information available on
the methodologies for symbol sign testing was inadequate.
A review of literature on sign testing shows that many
studies employed poor methods or poor research design. In
evaluating knowledge, Dewar recommended the use of a
multiple choice test instrument showing a picture or
drawing of the sign and asking for the meaning or driver
action. Showing a fihn with the sign in context could
also be used. The same approach could be appropriate for
legibility testing.

Designing a research study for symbol signs requires
a comprehensive approach incorporating several
methodologies. Dewar suggests that no single method is
totally adequate for any sign research since each sign
factor: meaning, attention value, legibility, processing
time, influence on driving behavior, (and resistance to
habituation), needs to be addressed in a unique fashion.
The methodologies and designs reviewed in studies for this

research have not been especially rigorous.

Symbol Sign Design

This discussion is limited to the design elements of
symbol signs and some more general sign consideration.
Extensive information is presented in the Traffic

Engineering Handbook (9) and the Manual on Uniform Traffic

 

 

Control Devices for Streets and Highways (16).

 

The essential symbol sign design criteria, according

36

to Markowitz, Lees, et al., (13) was to determine the
information needs of the driver in each specific traffic
situation. This could be accomplished by categorizing the
drivers into user groups and then directing the symbol or
sign to the audience. Signs must be specific to the task
and yet applicable to a general audience.

Six driver considerations, relative to signs, were

discussed in the Traffic Engineering Handbook.

 

1. Interpretation - word and symbol sign Inessages
must be reviewed for all possible
interpretations and misinterpretations.

2. Continuity - signs must be designed 1J1 context
with the other signs so as not to create
conflicts with similar signs in the system.

3. Advance Notice — signs must allow adequate
response time for the driver in each situation.

4. Relatability — sign messages should be presented
in the same information terms as identical
information would be available to the driver
from other sources.

5. Prominence — the design of the sign should be
able to supercede other demands for driver
attention.

6. Unusual Maneuvers — signing should be designed
to give drivers information at points where
unusual or unexpected maneuvers take place.

 

These considerations establish direction for the
designers of traffic control devices and especially for
symbolic messages.

Markowitz (13) also defined symbol design criteria

with emphasis on the information content and

 

37
communicability of the message. His recommendations
consisted of:
1. Each symbol should give all important

information in the statement it is picturing and
present the elements of information in priority
order.

2. The symbol should contain no unnecessary detail
that may distort the message being presented.

3. Commonality (with other symbols used in society)
should be incorporated whenever possible to
improve recognition of the symbol.

These criteria referred to the contextual design of
the symbol rather than the graphics. The necessary
information must be combined with as few irrelevant cues
as possible to avoid misinterpretation by the driver.

In discussing symbol signs, McLean (15) states that
every element of a sign is in fact a symbol: shape, color,
background, and object or graphics. A11 sign elements
convey meaning through symbolism and this is true even
with some word Inessages. Drivers use the shape of the
sign to perceive meaning in much the same way that the
graphics are utilized.

Stop, Yield, No Passing, and Railroad Crossing signs
are examples of single Classification signs. Markowitz
(13) claims that there is very little application of this
type of sign in the traffic system despite their high

level of effectiveness. The single classification signs

 

38

have limited attention except for the intended users, for
whom the impact is greatest. A related classification of
symbol signs, not employed in this country, involves
abstract images to present information. These symbols are
best suited for critical messages and, as with the single
classification signs, require intensive education of the
driving public upon installation. Allen (1),
investigating recognition distance of symbols, found that
correctness and longer perception distances are achieved
through the use of bold, simple, and unique graphics.
Symbols that convey a message with the least contradiction
and ambiguity in design are the most effective.

McLean (15) best describes the dilemma in symbol sign
design when he asserts that traffic and highway engineers
feel that they are sufficiently expert in signs and
symbols to design new signs themselves when, in fact, more
disciplines may need to be included. Symbols are becoming
widely used throughout our society to convey messages and
the transportation system has been flooded with uniform
and non—uniform issues alike. The discipline of highway
symbol design and application is not sufficiently
developed. The multidisciplinary and inter—disciplinary
approaches necessary to design effective symbol signs have

not been brought to bear on the problem.

39

W

The available research clearly demonstrated some
major gaps in what is known about drivers’ understanding
of symbol signs. The research by AAA (2) did not employ a
true random sample and used only five actual symbol signs
in the test. Two of the five signs have been consistently
identified in <other research as being the most widely
understood and recognized of all symbol signs.

No study has produced a significant correlation
between symbol sign knowledge and sex, yet differences
have been found within the age categories. The effects of
driving experience and driver education are not well
defined inn: both. tend ti) enhance performance (M5 symbol
sign tests. Performance on tests of the familiarity with
the symbols provided inconsistent results.

A strong indicator identified in the Mackie research
was the drivers' knowledge of the symbol sign
classification system, which, unfortunately, is not
utilized with standardized symbol signs in the United
States.

The research methodologies in the studies reviewed
did not address the reliability and validity of the
instruments, criteria. for determining when drivers know
and do not know the meaning of a sign, and test sign
selection criteria. These items are critical to reliable

research.

40

No research assessed the impact of discrimination
upon sign knowledge or of the influence of discrimination
as a source of invalidity. There was no resolution of the
contradiction between task loading and the reduced
effectiveness of symbol signs and time improved. response
time achieved through the application of symbols.
Research design has not accommodated these issues.

Symbol design is 1J1 its early stages (if development
in this country and elsewhere. While symbols are widely
used, the interdisciplinary and multidisciplinary
approaches needed. for comprehensive cmmfltui consideration
have not been instituted.

The primary benefits of symbolic messages are the
more immediate and accurate understanding of the Sign, and
the elimination of the need for language comprehension.
In multilingual and mobile societies, these elements are
becoming necessities.

In Chapter III, a description of the research design
and methodology is presented. The data collection and

analysis are also discussed in detail.

CHAPTER III

DESIGN AND METHODOLOGY OF THE STUDY

 

 

The principal objective of this study‘ was to assess
drivers' knowledge of selected traffic signs employing
symbolic messages. The study was intended to discern
differences between groups of drivers, which were based on
age, sex, driving experience and training, and their
knowledge of the selected symbol signs. A secondary
objective was to determine drivers' familiarity with symbol
signs.

Chapter II reviewed literature and studies relevant to
these objectives, ie., knowledge and familiarity. This
chapter deals with the following areas: (1) source of
data; (2) materials; (3) procedure of the study; (4)

research design; and, (5) procedure for analysis of data.

Source of Data

A test sample was drawn from drivers in southwestern
New Hampshire who were renewing their driver/operator
licenses. Permission was obtained from the Division of
Driver Licensing, Department of Safety, in New Hampshire,
to test renewal applicants at the testing stations after
they were administered the eye examination and before they
received their renewed photo license. Drivers were
randomly assigned renewal appointments by the lDivision of

Driver Licensing during the month of their birth.

41

42

Sample Employed

 

Two hundred and twenty—three examinees were
administered the test instrument for this study in December
1982 during the license renewal process at stations in
Keene and Hillsborough, New Hampshire. All renewal
applicants holding valid licenses and having driven during
time past year were tested. No discriminathma, in context
of race, creed, age, sex, or national origin, was exercised.

Subjects could not be required to complete the test as
it was not part of the state license renewal examination.
Drivers were asked to complete the test, though, as a part
of the renewal process without being given any option. By
prior agreement with the Division of Driver Licensing, any
driver who refused to take part in the test would be
excused without recourse. One male and four female
subjects, approximately two percent of the test population,
declined to respond to the test questions.

Eleven test returns were eventually eliminated due to
either illegibility or failure to meet the past year
driving criteria. The final sample size consisted (if 212

drivers who met all test requirements as specified above.

Research Materials

 

The materials for this study were limited to a fifteen
question Imlltiple-choice test, 51 response sheet for
demographics and item answers, and pencils. The test
instrument and response sheet are presented in Appendix A.

The test instrument was developed specifically for this

43

research project after an extensive search of related
literature failed to produce suitable items. Item bank
searches did not contain an acceptable number or quality of
questions with established validity cm: reliability ti) meet
the demands of this study. A summary of the process
employed in developing the instrumentation is presented
here, with a detailed description in Appendix B.

The instrument consisted of a fifteen item
domain—referenced test with an additional five items for
demographic information. Each multiple choice question was
presented with three foils accompanied by a full color sign
for reference to the item. Only upper case letters in 10
pitch were used in the type style to facilitate ease of
reading. The average reading level for the four pages of
the test was determined to be at a 4.2 grade level and
ranged from 3.0 ti) 5.5 for the entire instrument. Dr.
Glenna Mize, Reading Specialist in the Safety' Center at
Keene State College, estimated the reading level for the
twenty items using the Frye Readability Formula. The
reading level assessment is found in Appendix C.

Symbol signs of true color were obtained from the

pamphlet Lhfliiai States Ihmmi Symbol Signs (October 1979),

 

printed fur the Federal Highway Administration, U.S.
Department of Tiansportation, and affixed to the finmi for
each item. lime pages of the instrument were laminated and
stapled to enhance durability.

The basis of sign selection for research purposes was noted

44

as ea deficiency 111 prior studies. A serious attempt was
made to rectify this situation by developing a) logical and
systematic selection procedure.

This study employed a pmocess of content validity to
identify and select the signs deemed most important to the
driving task. Items were developed by the author for each
of the fifty—five symbol signs listed by the U.S.
Department of Transportation in the pamphlet noted above.
Four traffic engineering, traffic safety, and driver
licensing experts were asked to evaluate and rate each item
following the content validity assessment process developed

by Mussio and Smith in Content Validity: A Procedural

 

Manual.

Each expert was given a description of the content
domain ti) be tested anmi the test questions, and asked to
rate the relevance of the item ti) the domain using ea five
point scale. The recommendations and ratings of the
experts were recorded on the assessment form and the
interrater agreement and index of content validity' were
calculated.

The fifteen symbol signs receiving the highest average
ranking by the four experts were selected for inclusion in
the study. These signs were determined by the panel of
experts to lme the most essential to time driving task. I\
detailed discussion (if this process, and the accompanying
materials, is presented in Appendix B.

Statistical analysis consisted of applying

45

Kuder-Richardson Formula 21' (K-R21') to the ratings
provided by the four experts to obtain a correlation
representing interrater reliability and an index of content
validity. The index of content validity was established at
a level of r=.9455.

The level of reliability of the instrument was
established iii conjunction with the pilot study and set at
r=.979. The discussion of test instrument reliability

occurs elsewhere in this chapter under Research Design.

 

Procedure of the Study

 

Testing tduring time driver licensing process provided
an ideal setting and opportunity for this study. No time
requirements were established for the respondents and thus
no task loading was incorporated into time data collection
process. imme official environment (M5 the testing station
was used to promote acceptance of the testing.

The license renewal process in New Hampshire is
initiated with a renewal appointment issued to each
licensed driver in the state at four year intervals.
Renewal appointments are made during the month (if birth of
the licensee (ii a random basis as the renewal applications
are returned to the state office.

The setting within the testing stations consists of a
vision screening and photo area along with another area for
new driver licensing testing. After successful completion
of the vision test, the licensee has a photo identification

picture taken and must wait from three to fifteen minutes

46

for processing of the official license. It was during this
normal waiting period that the test subjects were asked to
complete the questionnaire.

Immediately after the photo was taken and before the
licensee exited the testing area, he or she was asked to
participate in the survey. The following approach was used
in each case:

"We are conducting a survey of driver's

knowledge of signs and I would like you to

answer some questions on signs while you wait

for your license photo to be developed."

After an indication of approval, each subject was
given a test form, answer sheet, pencil, and the following
instructions:

"Please begin by responding to the first five

questions on the answer sheet to give some

information about yourself. For each question,
circle the letter of the answer that is most
appropriate for you. Then go on to the sign
questions, read the question and select either

'A,' 'B,‘ or 'C' as the correct answer. For

each question, record your response on the

answer sheet by circling the letter you

selected. You do not need to put your name on

the answer sheet and please do not write on the

test form. Please return the completed forms to

me when you have finished."

The only action required of the subject was to read
the item and circle the appropriate letter response on the
answer sheet. No time limit was placed on the subject in
responding to the items. Assistance was provided only to
subjects who asked to have the instructions repeated.

Five of the licensees approached declined to complete

the survey. No reason was given in these cases and none

was requested. Upon return of the questionnaire the

47

respondents were thanked for their participation, given
their licenses, and exited the area. The test items were
neither scored nor answered before the subjects' departure.

Tests were administered at the testing stations in
Keene and Hillsborough, New Hampshire. The majority of all
renewal applicants are assigned to Keene as it is the
population center of the southwestern region. Hillsborough
was randomly selected from among the three part—time
testing stations to provide a representative sample of
drivers from outside Keene.

A total of two hundred and twenty—three (223) renewal
applicants was tested. One hundred and eighty—one (181)
drivers were tested in Keene on December 1, 2, 8, and 9,
1982. The remaining forty-three (43) were tested in
Hillsborough on December 9, 1982. The distribution of
Keene and Hillsborough subjects is roughly equivalent to
the population distribution within Keene and outside of

Keene in the testing region.

Research Design

A pilot study was conducted prior to formal testing to
assess the data collection procedures and to gather results
to establish the reliability of the instrumentation. In
the pilot study, the test was administered to fifty (50)
licensees. The proposed methodology for test
administration was evaluated and found to be acceptable,

based on low test subject procedural errors and

48

receptivity. No modifications were made to the
instructions, test materials, or method of presentation at
the close of the two days of pilot test. The pages of the
test form were laminated after the trial period because of
wear due to license applicants writing on the instrument.
Test reliability was established as a part of the
pilot study as no measure existed for the new instrument.
Kuder-Richardson formula 21' was selected for this
assessment because of its accuracy of estimation. The

formula employed in the calculations was:

K—R 21': 1 — .8M (K—M)

KV

In this formula:
M=the mean of the test scores

K=the number of items in the test
V2=the variance of the scores.

The following values were obtained from the tests:

M=12.38
K=15
V2=3l.7556

These calculations produced a coefficient of reliability
for the test instrument of: r=.9455. This level of
reliability was acceptable for the research purposes when
considered along with the level of validity of r=.979.
Coefficients in this range are considered exceptional in
test construction when a level of .90 is usually most

acceptable.

49

Research Hypotheses

 

The null hypotheses tested in this research were:

1. There is no significant difference between male
and female drivers' knowledge of symbol signs.

H01: lul—luz = 0

2. There is no significant difference in the
knowledge of symbol signs between drivers with
formal training and those without formal training
in the driving task.

H02: [ll-II, = 0

3. There is no significant difference in the
knowledge of symbol signs between the age
classifications of drivers.

Hos: #.-/12—11.-/1.—/1.-u.-u7=

4. There is no significant difference in the
knowledge of symbol signs between the experience
classifications of drivers.

H04: 41-42—ui—44—Ms—ue—x17—ua= o

The level of significance for all statistical tests

was set at .10.

Procedure for Analysis of Data

 

The validity and the reliability of the
instrumentation were determined prior to data collection as
described above. Two hundred and twenty—three (223) sets
of data were collected and two hundred and twelve (212)
were utilized.

All of the response sheets utilized in the data

50

analysis were individually numbered for identification
purposes, hand keyed to electronic media, and stored on
diskette. This entire process was duplicated producing two
complete data files that were loaded into the Digital/Vax
11/780 at Keene State College for comparison of the two
data files. An input error rate of .0026 was registered
and errors were reconciled against the original forms.

SPSS for VAX/VMS, Version M. Release 9.1, June 15,
1982, was selected as the program for statistical
analysis. The descriptive statistics (frequencies) were
generated through the use of the CROSSTAB feature. The
intragroup statistics were computed through the use of
"Procedure Breakdown" and "Procedure T—Test" in SCSS for
the variables of age, driving experience, sex and
training. The interactive SCSS statistical analysis
program, running on the Wang VSlOO, was employed to cross
check data, perform exploratory analysis, and for table
generation.

Differences in subgroup population means were tested

as follows:

 

Variable Name Statistical Test(s)
Age Eta, ANOVA, Linearity
Sex t—test

Driving Experience Eta, ANOVA, Linearity
Training t—test

Each item on the instrument was analyzed and the
frequency of each response to an item calculated. Null
responses were also tabulated to assess guessing. Drivers'

recognition of the symbol signs tested was computed at this

51

time and included as a descriptive statistic. The Pearson
Product Moment Correlation was employed to test the
strength of association between sign recognition rates and
correct response rates.

Statistical analysis of the relationships between the
groups and their knowledge of symbol signs was accomplished
using Pearson Product Moment and Point Bi—serial
correlations. The relationships between knowledge and the
variables of sex and training, both dicotomous, was
computed using the Point Bi—serial correlation. The
Pearson Product Moment correlation was employed to test the
relationship between the variables of age and driving
experience, both continuous, and knowledge of symbol signs.

Summary

A test instrument was employed to determine drivers'
knowledge of symbol signs during the license renewal
examination. A fifteen item domain—referenced test
instrument was developed for the study and it was
determined to have very high validity and reliability
coefficients. The instrument was constructed with high
legibility and readability. The sample consisted of two
hundred and twelve licensed drivers from southwestern New
Hampshire. Computerized data analysis was conducted using
SPSS and SCSS. The results of the data analysis are

presented in Chapter IV.

CHAPTER IV

ANALYSIS OF DATA

In Chapter Three, the methods and procedures of test
development and data collection for this study were
discussed. A domain referenced test was administered to
two hundred and twelve subjects, randomly selected on the
basis of license renewal appointment date and date of
birth. The data obtained was analyzed using SPSS and the
interactive SCSS.

Chapter Four provides a presentation and analysis of
the data collected. The elements of this chapter consist
of 1) Demographic Information; 2) Test Item Analysis; and,

3) Crosstabulations and Intragroup Statistics.

Demographic Information

Age and Sex

The age of the respondents was grouped into seven
categories as detailed in Table 1, which also summarizes
the breakdown by sex. Of the two hundred and twelve
respondents, six were in the sixteen to nineteen (16-19)
age group; fifty—five in the twenty to twenty—nine (20—29)
group; sixty-two in the thirty to thirty—nine (30—39)
group; thirty—seven in the forty to forty—nine (40—49)
group; thirty-one in the fifty to fifty—nine (50—59) group;
fifteen in the sixty to sixty-nine (60—69) group; and, six

in the seventy and over (70+) age group. One hundred and

52

53

Table 1

Age and Sex Distributions for Test Subjects

 

 

 

 

mm N TQML% ammANvEe
(16—19) 6 2.8 2.8
(20—29) 55 25.9 28.8
(30—39) 62 29.2 58 0
(40—49) 37 17.5 75 5
(50—59) 31 14.6 90.1
(60—69) 15 7.1 97.2

(70+) 6 2 8 100 0
TOTAL 212 100.0
SEX N TOTAL % CUMULATIVE %
FEMALE 114 53.8 53.8

MALE 98 46.2 100.0
TOTAL 212 100 0

 

fourteen (53.8%) Of the respondents were female and
ninety—eight (46.2%) were male.

Driving Experience and Driver Education

 

Driving experience was assessed as a factor Of the
number Of miles driven per week by' each respondent. The
mean for this sample population equaled 135 miles per
week. A breakdown Of the eight categories is presented in
Table 2 on the following page.

In the study sample, two drivers reported averaging
zero (0) miles per week; thirteen reported one to twenty
(1—20) miles per week; fifty—four reported twenty to fifty
(20—50) miles per week; sixty reported fifty to one hundred

(50—100) miles per week; forty reported one hundred to two

54

hundred (100—200) per week; twenty reported two hundred to
three hundred (200—300) miles per week; five reported three
hundred to four hundred (300—400) miles per week; and,
seventeen reported driving an average Of more than four
hundred (400+) miles per week.

The influence Of formal training, i.e. driver
education, on symbol sign knowledge was analyzed as a part
Of this project and is also presented in Table 2. One
hundred and eleven (52.4%) of the respondents had taken a
course in driver education. One hundred and one, or 47.6%,

had no formal training.

Table 2

Breakdown of Driving Experience and Training
for Test Subjects

 

MILES N TOTAL % CUMULATIVE %

 

DRIVING EXPERIENCE IN MILES PER WEEK

 

 

0 2 .9 .9
1—20 13 6.1 7.1
20—50 54 25.5 32.5
50—100 60 28.3 60.8
100—200 41 19.3 80.2
200—300 20 9.4 89.6
300—400 5 2.4 92.0
400+ 17 8.0 100.0
TOTAL 212 100.0
MILES N TOTAL % CUMULATIVE %
TRAINING
DRIVER EDUCATION 101 47.6 47.6
NO DRIVER EDUCATION 111 52.4 100.0

TOTAL 212 100.0

 

55

The fifth demographic item on the test instrument was
a data check to verify a parameter Of the study. A "no"
response to the fifth question, "Have you driven a motor
vehicle during the past year?", served to disqualify the
answers from the data analysis session. The research
definition for this project included only drivers who had

driven during the past year.

Test Item Analysis

 

This section Of the report summarizes the responses to
the fifteen test items used to assess knowledge Of symbol
signs. A copy of the test instrument is found in Appendix
A and in Appendix E, Tables E—l through E-15 are used to
present a breakdown Of the responses to each test item.
Crosstabulations are used in another section Of this
chapter to present test results with reference to the
sample subgroups Of age, sex, driving experience and
training.

The grand mean for the symbol sign test was 78.792%,
indicating that the test subjects, on the average,
correctly responded to 11.8 Of the fifteen items. The
average recognition rate (whether or not the sign had been
seen before) for all fifteen signs was 68.6%.

The effects of symbol sign recognition on symbol sign
knowledge were analyzed by testing the relationship between

the correct response rate and the recognition rate for each

 

56

item. The Pearson Product Moment Correlation was employed
to test the association between the correct response rate
and the recognition rate for the fifteen test items. A
mean value of 78.76% was Obtained for the fifteen items and
a mean value for the recognition rate was set at 68.6%.
The Pearson Correlation coefficient between the two sets of
data was r = .739, which was significant at the .001
level. Missing values, i.e. no response, were found for
3.71% of the possible item response cases.

Table 3 shows the correct and incorrect response rates

for each test item and the symbol sign recognition rates.

57

 

 

Table 3
Slnn r T 1 rr nse n R o niti n R f r T It m
N0 SIGN RECOGNITION
ITEM # CORRECT % TNFnRRFFT Z, ANSWER % YES N0, Z
1 181 85.4 28 13.2 3 1.4 187 22 88.2
2 126 59.4 84 39.7 2 0.9 199 9 93.8
3 178 84.0 25 11.8 9 4.2 128 79 60.4
4 200 94.3 10 4.8 2 0.9 205 4 96.7
5 61 28.8 125 57.9 26 12.3 49 161 23.1
6 200 94.3 12 5.6 0 0.0 206 6 97.2
7 170 80.2 27 12.7 15 7.1 117 93 55.2
8 175 82 5 34 16.1 3 1.4 173 35 81.6
9 152 71.7 52 26.5 8 3.8 149 57 70.3
10 151 71 2 49 25.2 12 5.7 129 78 60.8
11 193 91.0 15 7.1 4 1.9 178 21 84.0
12 202 95.3 6 2.8 4 1.9 191 18 90.1
13 176 83.0 14 6.6 22 10.4 48 158 22.6
14 132 62.3 72 34.0 8 3.8 98 109 46.2
15 208 98.1 4 1.9 0 0.0 176 31 83.0
MEAN VALUES 78.8% 3.71% 68.6%

r = .793

SIGNIFICANT AT .001 LEVEL

 

the

classification Of the symbol sign,

Listed below,

58

symbol signs employed in

or Construction, is given as a W, R,

RANK

1.

10.

11.

12.

13.

14.

15.

SYMBOL SIGNS (CLASS)
TWO WAY TRAFFIC (W)
LOW CLEARANCE (W)
DO NOT ENTER (R)
RIGHT CURVE (W)
SLIPPERY ROAD (W)
NO LEFT TURN (R)
KEEP LEFT (R)
NARROW BRIDGE (W)
MERGING TRAFFIC (W)
T—INTERSECTION (W)
MERGE LEFT (W)
DIVIDED HIGHWAY AHEAD (W)
WORKERS ON ROAD (C)
LEFT TURN ONLY (R)

CENTER LANE LEFT TURN ONLY (R)

ie.

this

or C respectively.

in order Of correct response

rate, are
study. The
Regulatory,

Warning,

CORRECT RESPONSE RATE

MEAN

98.

95.

94.

94.

91.

85.

84.

83.

82.

80.

71.

71.

62.

59.

28.

78.

1

JE- D.) N \l N U1 0 O 113 O I-b (A) DJ
o\° o\° o\° o\° o\° o\° o\° o\° o\° o\° o\° o\° o\° o\°

m
o\°

59

Crosstabulations and Intragroup Statistics

In SCSS, “Procedure Crosstabs" and "Procedure
Breakdown" were applied to the data to produce a variety of
crosstabulations to test for differences in subgroup means
and to establish measures of association within the sample
subgroups. These functions produced frequency
distributions, the statistical tests for correlations,
t—tests, and ANOVA. Crosstabulations and breakdowns were
produced for the variable pairs Of:

1. Knowledge with Age;

2. Knowledge with Sex;

3. Knowledge with Driving Experience; and,

4. Knowledge with Training.

'Procedure Crosstabs' in SCSS provides for the
calculation Of measures of association between joint
distributions Of two or more variables. 'Procedure
Breakdown' allows the calculation Of general measures of
central tendency, analysis Of variance, and linear
relationships. Both analytical tOOls can be used to
generate tables and graphs to present summary data.

The correlations applied to test for association were
the Pearson Product Moment Correlation and the Point
Bi—Serial Correlation. The Bi-Serial Correlation is a
special case Of Pearson that permits one of the variables
to be expressed as ea dicotomous variable while the other

has integer values. Both statistical tests used the same

 

6O

formula but the Bi—Serial Correlation used a dicotomous
variable coded 0,1 and an integer variable, rather than the
two customary integer variables for the Pearson Product
Moment Correlation. In reading any of the following
computer generated tables, the listed Pearson value is the
Bi—Serial value only when noted.

The t—test was used to test for differences in
subgroup means within the variables Of sex and training.
ANOVA was applied to test for differences between the
multiple subgroup means Of the variables Of age and driving
experience. Linearity was also tested as an element Of the
analysis Of these later variables.

Multiple breakdowns were performed using "Procedure
Breakdown" in SCSS for five variable sets to describe
differences within and between groups. Each table
presented in Appendix D describes the mean, standard
deviation, and number of cases for all subgroups Of the
variables. These breakdowns included:

1. Mean Test Scores by Sex and Training;

2. Mean Test Scores by Age and Sex;

3. Mean Test Scores by Age and Training;

4. Mean Test Scores by Experience and Sex; and,

5. Mean Test Scores by Experience and Training.

Analysis of the Variable Age

 

The Pearson Product Moment was used to test the level

of association between the variables Of age and knowledge

 

61

and. a coefficient of r = —.272, which was significant at
the 0.000 level, was produced.

Testing the differences between the subgroup means
involved three tests: Eta, ANOVA, and a test of
linearity. The null hypothesis stated there were no
significant differences between the subgroups in the
variable age. A statistical presentation of the variable
age is found in Table 4. The mean test scores, broken down
by age and sex, and by age and training, are presented in

Appendix D of this report.

Table 4

Breakdown of Knowledge Test Scores by Age Groups

 

ETA, ETA SQRD = .3539 .1253
CORRELATION = —.2723
SIGNIFICANCE = 0.000
Age Groups
1. 2. 3. 4. 5. 6. 7. TOTAL
16—19 20~29 30739 40—49 50759 60—69 70+
MEAN 85.667 80.218 83.355 _80.378 69.548 68.933 74.333 78.792
SUM 514.000 4412.000 5168.000 2974.000 2156.000 1034.000 446.000 16704.000
STD DEV 6.653 16.341 10.496 13.933 17.804 15.563 11.690 15.073

VARIANCE 44.267 267.026 110.167 194.131 316.989 242.210 136.667 227.198

N 6 55 62 37 31 15 6 212

 

62

The ANOVA statistic tested the equality of the seven
subgroup means by analyzing Observed variability. The
Obtained value of F = 4.8930, significant at the .0001
level, indicated that the means were probably unequal.
With F = 4.8930, significant at a level Of .0001, it was
highly unlikely that equality Of the means existed.
Significant differences existed between the subgroup means
of the variable age.

An index of the variability attributed to the
differences between the subgroup means is the Eta
statistic. The variability due to subgroup mean
differences in the age variable was .1253.

Linearity was tested to assess the presence Of a
linear relationship between age and knowledge. The
Obtained F—value of 17.3772, significant at the 0.0000
level, indicated a strong linear relationship. The null
hypothesis that no significant differences existed between
the subgroup means was rejected.

A summary Of the Eta, ANOVA, and linearity tests

follows in Table 5.

63

Table 5

Summary of Statistical Analysis for the Variable Age

 

BREAKDOWN OF KNOWLEDGE — TEST SCORE

ETA, ETA SQRD = .3539 .1253

CORRELATION = .2723

ONEWAY ANOVA: SUM OF SQUARES DEG FR MEAN SQUARE
BETWEEN GROUPS 6005.3124 6 1000.8854
WITHIN GROUPS 41933.5555 205 204.5539
TOTAL 47938.8679 211

F = 4.8930*

TEST OF LINEARITY: SUM OF SQUARES DEG FR MEAN SQUARE
LINEARITY 3554.5809 1 3554.5809
DEV FROM LINEARITY 2450.7316 5 490.1463
F(LINEARITY) = 17.3772**

F(DEVIATION) = 2.3962***

*SIGNIFICANT AT .0001 LEVEL
**SIGNIFICANT AT .0000 LEVEL
***SIGNIFICANT AT .0387 LEVEL

 

Analysis of the Variable Sex

 

The two categories within the variable sex were coded 0
for female respondents and l for male respondents. To test
the level of association, the Bi—Serial Correlation was
computed and a value of r = .171 was derived. The
correlation was significant at the 0.006 level.

A t—test was applied to assess the differences between
the mean scores for male and female test subjects. For
male subjects the mean equaled 81.919 and a mean of 75.356

was Obtained for female subjects with standard deviations

 

Of 12.352 and 16.691

significant at the .012

respectively. A

level,

 

64

t—value of 2.54,

was obtained. The null

hypothesis that no significant differences existed between

male and female subjects was rejected.

Table 6 details summary statistics from the t—test for

the variable sex.

TABLE 6

T—Test Results for Male and Female Subjects in
the Variable Sex

 

 

 

VARIABLE GROUP N MEAN STD DEV STD ERR
MALE 98 81.571 14.087 1.423
FEMALE 114 76.404 15.538 1.455
SEPARATE VARIANCE
DIFFERENCE BETWEEN GROUPS
VARIABLE MEAN STD ERR t DF PROB
KNOWLEDGE 5.168 2.035 2.54* 209 .012
* SIGNIFICANT AT .012 LEVEL
Analysis of the Variable Driving Experience
The relationship between the variables Of driving
experience and knowledge was tested with the Pearson
Product Moment Correlation. A value of r = .226, which was
significant at the 0.000 level, was Obtained. The

breakdown of the variable driving experience

in Table 7.

is presented

 

65

Table 7

Cell Statistics for the Variable Driving Experience

 

BREAKDOWN OF KNOWLEDGE — TEST SCORE

ACROSS 1 DRIVING EXPERIENCE (IN MILES PER WEEK)

LOW MILES PER WEEK
LEVEL 1. 2. 3. 4. 5. 6. 7.
0 1-20 20—50 50—100 100—200 200—300 300—400
MEAN 73.500 68.769 77.241 78.667 79.317 80.700 82.800
STD DEV 9.192 20.187 14.182 17.296 13.648 10.147 9.960

VARIANCE 84.500 407.526 201.130 299.141 186.272 102.958 99.200

N 2 13 54 60 41 20 5

HIGH

8.

400+

87.765

10.680

114.066

17

TOTAL

78.792

15.073

227.198

212

 

66

The mean test scores for time variable (driving
experience, broken down by sex and by training, are
presented in Appendix D of this report.

Testing the differences between time subgnmug means Of
the variable driving experience involved the Eta statistic,
ANOVA, and a test Of linearity. ANOVA was employed to test
the equality between the eight subgroup means of the
variable driving experience. The Obtained F—value of
1.9634 was significant (M: the 0.0616 level emmi suggested
that the subgroup means were probably not equal. A
probability CM? 0.0616 indicates that it was unlikely that
equality of the subgroup means existed.

The variability that could be attributed to differences
in subgroup means was calculated using time Eta statistic.
Subgroup mean differences accounted for .0631 of the
variability.

The absence of a linear relationship was tested between
the variables of driving experience and knowledge. An
Obtained F—value Of 14i1502, which was significant at the
0.001 level, revealed the presence of a strong linear
relationship.

Based on these tests, the null hypothesis that no
subgroup differences existed in the variable driving
experience was rejected.

Table 8 contains a summary of the Eta, ANOVA, and

linearity statistics for the variable driving experience.

67

Table 8

Summary of Statistical Analysis for the Variable
Driving Experience

 

ETA, ETA SQRD = .2512, .0631

ONEWAY ANOVA: SUM OF SQUARES DEG FR MEAN SQUARE
BETWEEN GROUPS 3025.9197 7 432.2742
WITHIN GROUPS 44912.9483 204 220.1615
TOTAL 47938.8679 211

F = 1.9634*

TEST OF LINEARITY: SUM OF SQUARES DEG FR MEAN SQUARE
LINEARITY 2454.8342 1 2454.8342
DEV FROM LINEARITY 571.0854 6 95.1809
F(LINEARITY) = 11.1502**

F(DEVIATION) = .4323***

*SIGNIFICANT AT .0616 LEVEL
**SIGNIFICANT AT .0010 LEVEL
***SIGNIFICANT AT .8568 LEVEL

 

Analysis of the Variable Training

 

The ti“) categories twithin the 'variable training were
tested find their level CM? association using time Bi—Serial
Correlation. A coefficient Of r = .171 was Obtained, which
was significant at the 0.006 level.

In applying the t—test to assess the differences
between the mean scores Of subjects, a mean of 81.919 was
Obtained for subjects who had completed a course 1J1 driver
education. The mean for subjects who had not taken a

driver education course was 75.356. The difference between

68

the subgroup means was 6.562 and a t—value of 3.19,
significant at the 0.002 level, was derived from the
computations. As a result of the significant differences
between the subgroup means, the null hypothesis that no
differences existed, was rejected.

Test statistics for the variable training are
summarized in Table 9. Mean test scores for subjects with
training and without training, broken down by sex, are

presented in Appendix D.

Table 9

t—Test Results for the Variable Training

 

GROUP 1: TRAINING (DRIVER EDUCATION)
GROUP 2: NO TRAINING (NO DRIVER EDUCATION)

VARIABLE GRP N MEAN STD DEV STD ERR
GROUP 1 111 81.919 12.352 1.172
GROUP 2 101 75.356 16.994 1.691

SEPARATE VARIANCE

DIFFERENCE BETWEEN GROUPS

VARIABLE MEAN STD ERR t DF PROB

KNOWLEDGE 6.562 2.058 3.19* 181 .002

*SIGNIFICANT AT .002 LEVEL

 

69

SUMMARY

Statistical analysis of the test data, using SPSS and
SCSS, produced a variety of descriptive statistics covering
demographic features and item analysis. Also generated
were the tests of association using Pearson Product Moment
and Bi-Serial correlations. At a third level, the Eta
statistic, ANOVA, and a test of linearity were employed to
analyze differences between the subgroup means for each Of
the variables.

Each of the four null hypotheses were rejected. A
level of significance Of 0.10 had been established as a
basic parameter for decision making in accepting or
rejecting the null hypothesis. Significant differences
were found in the subgroup means for the variables of age,
sex, driving experience and training. In all cases, the
probability Of obtaining the observed results by chance was
less than 0.10.

The item analysis identified the symbol signs that were
most frequently identified correctly and incorrectly by the
test subjects. Two Way Traffic, LOW Clearance, Slippery
Road, Right Curve, and DO Not Enter, all received correct
response rates in excess Of 90%. Symbol signs registering
incorrect response rates below 75% were: Center Lane Left
Turn Only; Right Turn Only; Workers On Road (Construction);

Merge Left; and, Divided Highway Ahead.

70

An assessment Of the relationship between having seen
the symbol sign.1flmtke driving (recognition) and knowledge
of the sign (correct response) was performed. A Pearson
Product Moment Correlation coefficient Of r == .739 was
Obtained. This result was significant at the 0.001 level.

Findings, conclusions, recommendations, enmi discussion
relevant to this study are found in the following chapter.
A correlation matrix for the test variables is presented in

Appendix D.

 

CHAPTER FIVE

SUMMARY, FINDINGS, CONCLUSIONS, RECOMMENDATIONS,
AND DISCUSSION

 

The final chapter of this report will present: 1) a
summary Of the study; 2) conclusions based on the findings
Of the research; 3) recommendations for further study; and,

4) a discussion Of relevant issues.

Summary

The principal Objective of this study was to assess
driver's knowledge and recognition of symbol signs used in
the traffic environment. The differences between groups of
drivers, delineated on the basis of age, sex, driving
experience, and training were studied.

A fifteen item domain referenced test instrument,
shown in Appendix A, was developed for this study and

employed as the mediUNT for assessing driver knowledge of

symbol signs. The content validity of the instrument, set
at r = .979, was established using a panel Of traffic
experts. Test validity was determined through a field

trial after which the Kuder—Richardson Formula 21' (K-R
21') was applied to the test results. The level Of
validity was set at r = .9455.

The test sample was comprised Of two hundred and
twelve (212) drivers, selected on the basis of license
renewal date, from southwestern New Hampshire who were
renewing their driver/Operator licenses. Tests were

71

72

administered during December 1982 at the licensing stations
in Keene, Peterborough, and Hillsborough.

Data analysis was performed using both SPSS and the
interactive SCSS. In addition to test item analysis, the
association between the study' variables and the knowledge
scores was calculated using the Pearson Product Moment and
the Bi—Serial correlation coefficients as appropriate.
Intragroup differences were measured using the t—test,

ANOVA, the eta statistic, and the test of linearity.

Findings

With respect to the data analysis, this study
answered several questions:

1. Is there a Significant difference in the
knowledge of symbol signs between the age classifications
of drivers?

Based on mean scores for each Of the seven subgroups
of the variable age, it was determined that age was a
factor in symbol sign knowledge. The strong linear
relationship along the groups showed that as age increased,
symbol knowledge decreased. Over the individual test
subjects, the Pearson Product Moment correlation also
demonstrated the same age relationship with a negative
correlation value.

2. Is there a significant difference between male
and female drivers' knowledge Of symbol signs?

The difference of 5.168 between the mean test scores

of male (81.571) and female (76.404) drivers was

 

 

73

significant. In breaking down sex difference by age, male
drivers achieved higher mean scores than their female
counterparts in all age categories.

3. Is there a significant difference in symbol sign
knowledge between the driving experience classification of
drivers?

The Pearson Product Moment correlation showed a
significant relationship between the number of miles driven
per week and the knowledge scores of individual drivers.
The positive correlation demonstrated that as mileage
increased so did test scores. Significant differences were
also found within the eight experience classifications and
a positive linear relationship was established. A
breakdown of the driving experience variable by sex did not
produce a clear definition Of differences.

4. Is there a significant difference in the
knowledge Of symbol signs between drivers with formal
training and those without formal training in the driving
task?

The presence of driver education among test subjects
resulted in the mean score difference of +6.562. The
difference between the mean scores for drivers with driver
education (81.919) and those Without driver education
(75.356) was found to be significant. Clear definitions Of
differences were produced in breaking down training by sex
and driving experience. The differences in mean scores by

sex held up in the presence of training, as did the

 

74

reported differences produced by driving experience.

The effects Of symbol sign recognition were analyzed
by testing the relationship between the correct response
rate for each test item and the corresponding recognition
rate. Sign recognition and sign knowledge were related
based on the Obtained correlation coefficient of r = .739.

Fifteen symbol signs, used to provide information in
the traffic environment, were tested in this study. Each
sign was identified as critical to the driving task by the
panel Of experts. Listed below, in order Of correct

response rate, are the symbol signs employed in this study.

RANK SYMBOL SIGNS (CLASS) CORRECT RESPONSE RATE
1. TWO WAY TRAFFIC (W) 98.1%
2. LOW CLEARANCE (W) 95.3%
3. DO NOT ENTER (R) 94.3%
4. RIGHT CURVE (W) 94.4%
5. SLIPPERY ROAD (W) 91.0%
6. NO LEFT TURN (R) 85.4%
7. KEEP LEFT (R) 84.0%
8. NARROW BRIDGE (W) 83.0%
9. MERGING TRAFFIC (W) 82.5%

10. T—INTERSECTION (W) 80.2%

11. MERGE LEFT (W) 71.7%

12. DIVIDED HIGHWAY AHEAD (W) 71.2%

13. WORKERS ON ROAD (C) 62.3%

14. LEFT TURN ONLY (R) 59.4%

o\°

15. CENTER LANE LEFT TURN ONLY (R) 28.8

75

Conclusions

 

Based on the data analysis, this study' produced the
following conclusions.

1. Younger drivers are rmnie knowledgeable CHE symbol
signs than Older drivers.

2. Male drivers are more knowledgeable Of symbol signs
than female drivers.

3. Exposure to symbol signs, as measured in miles
driven per week, influences a driver's knowledge of
symbolic messages.

4. Driver education has e1 significant positive inmact
on knowledge of symbol signs.

5. There is a strong relationship between symbol sign

knowledge and whether or not the symbol sign has been seen

by time test subject. Symbol sign recognition influences
knowledge.
6. The best known symbol signs are Two Way Traffic, Low

Clearance, DO Not Enter, Right Curve, and Slippery When Wet.
7. The least known symbol signs are Center Lane Left
Turn Only, Left Turn Only, Workers On Road, and Merge Left.

Recommendations for Further Study

 

1. This study should be replicated in a larger
geographic area, vniii an increased sample size to validate
these findings. A wider demographic distribution will
reduce the effects of any possible unknown and uncontrolled

variables.

 

76

2. The scope of the test instrument should be
expanded ti) include signs timn: present Opposite or
conflicting Imeanings 111 order ti) test. drivers ability' to
discriminate between such signs.

3. The symbol sign test should be converted to
another medium, such as photographic slides, in order to
present the sign in a traffic scene with appropriate
distractions.

4. A study should be designed and conducted to assess
the efficiency Of symbol Signs in presenting messages in
the traffic environment.

5. Other types Of traffic control devices, ie.
delineators and pavement markings, that are used in
conjunction with symbol signs, should be studied to assess
the potential for presenting conflicting messages.

6. Finally, a further assessment should be conducted
to determine the source of the positive impacts on symbol
sign knowledge timfl: has been produced by driver education
programs in southwestern New Hampshire.

Recommendations

 

1. In) information. progrmn should lme established iii
New Hampshire to educate drivers about symbol signs with
special emphasis on Older drivers.

2. The driver licensing examinations in New Hampshire
should test the symbol signs that have been identified in

this study as being critical to the driving task.

77

3. A uniform graphic representation for the intensity
of the hazard (n: the situation should tme developed and
incorporated into symbol signs.

4. Word messages should be included with complex
symbol signs until driver knowledge improves through
training, public information, or familiarity.

5. Conflicting messages, presented through differing
types (ME traffic control devices, should be eliminated in
complex traffic situations.

Discussion

 

The significance (ME this study' was :hi providing an
understanding of driver's knowledge of symbol signs and the
basis :flor improving that knowledge. In relation ti) other
studies on symbol signs reviewed in this report, this study
was based (it the largest randONI sample (if test; subjects.
It was also the only study to develop a systematic
technique for time evaluation, selection, and inclusion Of
symbol signs in a test instrument.

A program to improve sign knowledge can be approached
in. a nmnme selective [nanner since it is now possible to
distinguish between drivers who do and do not know selected
signs. By determining the signs that are best known by
drivers, and relating this information to demographic
variables 11) the driving population, educational programs
can be targeted to selected groups.

The knowledge of symbol signs provides an indicator Of

the effectiveness of the sign message, which can be defined

78

as the ability Of a message to induce a desired behavior in
a driver. Effectiveness is dependent upon the application
of the Sign, attention value Of time graphics, selective
use, and a clearly recognizable message. In available
research reports, symbol signs are generally considered to
be more effective than word message signs. The
characteristics that make these signs more effective,
however, have not been well defined.

If attention value of the Sign is a critical factor in
sign knowledge, and a) strong logical argument can be made
for this case, it must be associated with recognition and
recall. Testing effectiveness through attention value will

encounter a major source of invalidity in driver

discrimination. Discrimination involves the ability of the
driver to selectively process stimuli from the
environment. An essential part (ME discrimination entails

ignoring irrelevant information (n: disgarding information
once it becomes irrelevant. Assessing attention value in a
dynamic format (inflrl prove difficult if time test subject
drivers employ the process Of discrimination effectively.

A more reliable indicator Of attention value would be
derived fitmi testing signs iii a highly structured
environment that requires some element of volition on the
part Of the test subject. The key to such a test would be
in defining the possible influences on driver actions from
the environment that may supplement the sign message and

influence the target volition.

79

D0 this study, emphasis was focused on knowledge and
understanding of symbol signs rather than detection and
identification. Detection and identification serve to
answer the question Of whether or not the sign was Observed
in the traffic environment by the driver. Knowledge and
understanding, on time other' handq are ‘tested ti) evaluate
whether or not the driver knows the appropriate response in
relation to a given sign message. Detection and
identification are based on the cognitive processes of rote
memory. Knowledge and understanding require higher level
thinking processes Of an evaluative format, especially when
the sign is tested in a dynamic scene.

The studies conducted by Mackie (12), Dewar (4), Drory
and Shinar (6), and Roberts (17) relied on driver recall as
a critical element of the test process.

The shortcoming though, of testing symbol sign
knowledge, with either level Of emphasis and in any format,
is that neither can guarantee an apprOpriate response ti) a
traffic situation as the result of the presence Of an
effective message. The inherent complexity (if the driving
task dictates otherwise.

The information presented by symbol signs has some Of
the same shortcomings as vmnii message, diagrammatic, and
changeable message signs. This study (mu) support several
Observations in this respect, though not necessarily in

strict empirical terms.

80

1. The complexity of the graphics of symbol signs is
a determining factor in the efficiency of the message
presented to the driver. Allen (1) cited graphic
complexity as a limitation Of signs and the test results Of
this study supports the assertion. The four signs with the
lowest correct response rate (Center Lane Left Turn Only,
Left Turn Only, Workers On Road, and Divided Highway Ahead)
have the most complex and least specific graphics Of the
fifteen signs tested.

2. Symbol signs perform an important function by
eliminating the need for reading skills, but the
requirement that the driver receive accurate information
from the sign still exists. More than fifteen percent of
the drivers in the study sample received inaccurate
information in the test situation on the nine lowest ranked
symbol signs. Allen's conclusions on the limitations
created by the complexity Of the graphics again holds true
in this selection of nine symbol signs, with the possible
exception of the Merging Traffic and T—Intersection items.

3. The six highest ranking symbol signs in terms of
correct response rate all contain features that aid in
efficiency Of the message and driver knowledge. These
consisted Of:

A. Well recognized graphic features such as the red

prohibition symbol (NO Left Turn);

B. The incorporation of a simple word message as an

element Of the sign (DO Not Enter); or,

 

81

C. Traditional symbols that have been used in the
traffic environment since vmibl before the adoption Of
modern symbol signs.

4. Gordon (8) and Roberts (17) reported that the
efficiency Of intricate graphics tended to degrade in
complex situations. The tJM) lowest ranking signs (ii the
correct response rate scale in this study (Center Lane Left
Turn Only and No Left Turn) are appropriate examples of
this concept. The former contains relatively intricate
graphics but a more substantial problem exists in that both
fail to accurately mirror the complimentary pavement
markings that drivers encounter.

Both signs are applied in complex traffic environments
to aid in lane selection and their use is dictated by high
vehicular' volumes. Complex ‘traffic situations Often. lead
to incorrect lane selection and vehicle position decisions
on the part Of the driver. In the case Of these two signs,
the addition of 23 lane position reference ti) the graphics
may enhance driver decisions by serving as a mirror (M3 the
roadway markings. The degradation Of symbol sign
efficiency, in complex traffic situations, may be the
result Of the lack Of specificity in the symbolic reference
rather than the intricacy of the graphics.

5. THme reliability of time messages presented fur the
lowest ranking signs :hi terms (Hf correct response rate is;
subject ti) question. Ihi most cases, the incorrect

responses to an item were divided over the three foils,

82

indicating that the test subjects were developing multiple
interpretations Of the meaning Of the symbol. A
requirement for an effective symbol sign is that it present
a singular message to all drivers.

6. A drawback Of symbol signs, over diagrammatic and
changeable message signs, is that in most cases they do not
reflect the intensity Of the hazard or the situation that
the driver may encounter. An approach ti) overcome this
deficiency would be the addition Of a uniform graphic
representation for the intensity of the situation or hazard

to the border Of the Sign.

BIBLIOGRAPHY

10.

83

REFERENCES CITED

Allen, R. Wade, et a1. Age Effects on Symbol Sign
Recognition. (Report NO. FHWA/RD—80/126)
Washington, D.C.: Federal Highway Administration,
December 1980.

 

 

American Automobile Association. Fowler, P. &
Hulbert, EL Motorists Understanding of Tiaffic
Control Devices, Test II. Falls Church, VA.: AAA
Foundation for Traffic Safety, December 1980.

 

 

Brinn, 11. Personal Communication, New Hampshire
Department Of Public Works and Highways, October 1982.

Dewar, R.E. Methodology in Tiaffic Sign Evaluation.
Paper presented at the International Conference on
Highway Sign Symbology. Washington, D.C., 1972.

 

Dewar, R.E. & Swanson, H.A. Recognition Of Traffic
Control Signs. Ann Arbor: University of NHchigan,
Highway Safety Research Institute, 1972.

 

 

Drory, A. & Shinar, D. "The Effects Of Roadway
Environment and Fatigue on Sign Perception". Journal
of Safetngesearch. Spring 1982, Vol. 13. NO. 1, New
York, 1982.

 

Emery, M. If You Don't Know Road Signs - It Could
Hurt You. Unpublished survey. East Lansing, MI,
Highway Traffic Safety Center, Michigan State
University. October 1978

 

 

 

Gordon, D.A. "Evaluation of [flagrammatic Guide
Signs". Motorists Information Systems, NO. 414.
Washington, D.C.: National Academy Of Sciences,

Highway Research Board.

Institute (ME Traffic Engineers. Traffic Engineering
Handbook. 1976.

 

Janda, H.F. & Volk, W. N. Effectiveness of Various
Highway Signs. Washington, D.C.: Highway: Research
Board, 1934.

 

 

ll.

12.

13.

14.

15.

16.

17.

18.

84

Kato, S. A Universal Language for the New Human
Environment. Luncheon Address, International

 

 

Conference on Highway Sign Symbology, Washington,
D.C., June 1972.

 

 

Mackie, A. M. Progress in Learning the Meaning Of
Symbolic Traffic Signs (RRL Report LR 91).
England: Ministry’ of Transport, Road Research

Laboratory, 1967.

Markowitz, J. & Lees, J. W., et al. An Investigation
of the Design and Performance of Traffic Control
Devices. Cambridge, MA.: Bolt Beranek and Newman,
Inc., BBN Report NO. 1726, December 1968.

 

 

 

 

Mast, 'T. 0L & Kolsrud, G. S. Diagrammatic Guide
Signs for Use on Controlled Access Highways. (Report
No. FHWA—RD—73-21). Washington, D.C.: Federal

Highway Administration, December, 1972.

McLean, K. G. Some Methodologies Applied to SmeOl
Evaluation iii Canada. Paper presented an: the
International Conference (n1 Highway Efirui Symbology,
Washington, D.C., June 1972.

 

 

Manual on Uniform Traffic Control Devices for Streets
and Highways. Washington, IL (3.: U.S. Department of
Transportation, Federal Highway Administration, 1980.

 

 

Roberts, A. W. Diagrammatic Sign Study. Washington,
D.C.: National Academy Of Sciences, Highway Research
Board, Motorists Information Systems, NO. 414.

 

Changeable Message Signs. Washington, D. C.:
Transportation Research Board, National Research
Council, (Report No. 61), July 1979.

 

SUGGESTED READINGS

 

 

 

Bogue, B. C. Your Drivers Exam and Road Test.
Oswego, IL.: National Traffic Safety Foundation,
1977.

Development Of a National Iten1 Bank. for Tests of
Drivipg Knowledge. Washington, D. C.: U.S.
Department of Transportation, National Highway

Traffic Safety Administration, July 1974. (NTIS No.
FH—11-7616)

10.

11.

85

Dudek, L. L., et al. Human Factors Requirements for
Real-Time Motorists Information Displays, Vol. 1.

 

 

Design Guide. Washington, IL (3.: U.S. Department of
Transportation, Federal Highway Administration,
September 1978.

Forbes, T. W. et al. A Study Of Traffic Sign
Requirements (II). East Lansing, MI.: Michigan
State University, 1964.

 

Gurney, G. F. et al. "Evaluation of Yellow-on—Brown
Road Signs for the Adriondack Park (Abridgment)".
Traffic Control Devices, Visibility enmi Geometrics,

 

Transportation. IResearch. ‘Record 681. 1Nashington,
D.C.: National Academy Of Sciences, 1978.

Holahan, C. J. et al. "Relation Between Roadside
Signs and Traffic Accidents". Road User Information
Needs, Pedestrian Movement and Bigycle Travel

 

 

Patterns, Transportation Research Record 683.
Washington, D.C.: National Academy of Sciences, 1978.

Pain, R. FR 2; Knapp. B. (L "Experimental Evaluation
of Delineation Treatments for Special Use Lanes".
Human. IFactors and Motorists Information Needs.
Transportation Research Record 782. WMshington,
D.C.: National Academy Of Sciences, 1980.

 

 

Significant Points from the Diagnostic Field
Studies. (Research iReport 1%). 606—4). College
Station, TX. : Texas A & M University, Texas

Transportation Institute.

Stockton, W. R. & Dudek, L. L. "Legibility Study of a
Lamp Matrix Sign". (Abridgment) Road User
Information Needs, Pedestrian Movement and Bicycle
Travel Patterns, Transportation Research Tuaiond 683.
Washington, D.C.: National Academy Of Sciences, 1978.

 

 

 

 

Stoke, C. B. "Effectiveness of Written Tests of
Driver's Knowledge Of Rules Of the Road". Human
Factors and. Motorists Information Needs.
Transportation. Research. Record 782. TNashingtOn,

D.C.: National Academy of Sciences, 1980.

Weaver, G. I). & Woods, D. L. Passing and NO Passing

 

 

Zones: Signs, Markings and. Warrants. (FHWA Report
No. RD—79-5) Washington, [L C.: U.S. Department Of
Transportation, Federal Highway Administration,

September 1978.

12.

86

 

Wootton, H. J. & Burton, R. S. "Improving the
Accuracy of Information of Direction Signs" . Human
Factors and Motorists Information Needs.
Transportation. Research. iRecord. 782. ‘Washington,

D.C.: National Academy of Sciences, 1980.

APPEND ICES

 

87

APPENDIX A

TEST INSTRUMENT AND ANSWER FORM

 

88

PLEASE N NOT WRITE ON THESE PAGES

 

 

 

 

 

 

 

 

 

1. nus SIGN MEANS:
A. No TURNS
n. LEI-r TURNS ALLoer
c. No LEFT TURNS ALLoer
HAVE you 11er SEER nus SIGN V8111: DRIVING? 111:5 No
2. nus SIGN MEANS:
A. nu: INDICATED TURN MUST 131: MADE
ONLY 1; No TURNS ARE ALLOVED
c. THEUNEMAYBEUSEDTOMAKEALEFTTURN
HAVE YOU EVER SEEN nus SIGN 111-111.5 DRIVING? YES NO
3. nus SIGN MEANS:
' A. KEEP LEI-'1'
8. LANE CLOSED AHEAD
C. VEHICLES APPROACHING ON LEFT
HAVE YOU 1:er SEEN nus SIGN 111111.}: DRIVING? YES NO

A. NO PARKING ANYTIME
B. DO NOT ENTER THIS STREET OR ROAD
C. mr ONLY

 

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES NO

 

5. THIS SIGN MEANS:

| A. DIVIDED HIGHWAY AHEAD

ONLY B. LEFT TURNS ONLY AI INTERSECTIONS
C. CENTER LANE FOR LEFT TURNS ONLY

 

 

 

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES NO

859

-2-

UPON SEEING THIS SIGN A DRIVER SHOULD:

A. SLOW AND LOOK POR RIGHT CURVE
E. HATCH FOR TRAFFIC ON SIDE ROADS
C. PROCEED AT NORHAL SPEED

6

HAVE YOU EVER SEEN THIS SIGN HHILE DRIVING? YES NO

7. UPON SEEING THIS SIGN A DRIVER SHOULD:

A. PREPARE TO TURN LEFT 0R RIGHT
E. DRIVE AT A SAPE SPEED
C. REDUCE SPEED AND DRIVE WITH CARE

9

HAVE you EVER SEEN nus SIGN HHILE DRIVING? us no

UPON SEEING THIS SIGN A DRIVER SHOULD:

A. HATCH FOR TRAFFIC ENTERING PRO! RIGHT
B. PREPARE TO STOP
C. MERGE UITH TRAFFIC

6

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES NO

9. UPON SEEING THIS SIGN A DRIVER SHOULD:

A. HATCH FOR ON-COHING TRAFFIC
D. HERGE LEFT
C. HATCH POR LOU SHOULDER

O

HAVE YOU EVER SEEN THIS SIGN HHILE DRIVING? YES NO

10. UPON SEEING THIS SIGN A DRIVER SHOULD:

A. LOOK FOR THO-HAY TRAPPIC AHEAD
3. MOVE RIGHT TO AVOID AN DESTRUCTION
C. EXPECT A DIVIDED HIGHHAY

.

HAVE YOU EVER SEEN THIS SIGN UHILE DRIVING? YES NO

90

-3-

11. UPON SEEING THIS SIGN A DRIVER SHOULD:

A. WK FOR WET SLIPPERY ROAD
D. EXPECT A ROAD POR CARS ONLY
C. LOOK FOR A SERIES OF CURVES

HAVE YOU EVER SEEN THIS SIGN ”NILE DRIVING? YES NO

12. UPON SEEING THIS SIGN A DRIVER SHOULD:

A. EXPECT ROAD TO NARRW TO 12 FEET 6 INCHES
E. EXPECT LW CLEARANCE 0F 12 FEET 6 INCHES
C. USE PARKING SPACES 12 FEET 6 INCHES

HAVE YOU EVER SEEN THIS SIG! WHILE DRIVING? YES m

13. THIS SIGN MEANS:

A. NARRW ERIME
B. DESTRUCTION IN ROAD
C. SOFT SHOULDER

HAVE YOU EVER SEEN THIS SIGN UHILE DRIVING? YES NO

THIS SIGN MEANS:

A. ELAGHAN AHEAD
3. ROAD HORK
C. VORKERS 0N ROAD

 

HAVE YOU EVER SEEN THIS SIGN HHILE DRIVING? YES NO

15. THIS SIGN HEANS:

A. THO-HAY TRAFFIC
3. STOP FOR ON-COHING TRAFFIC
C. DIVIND ROAD

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES NO

YES

YES

YES

YES

YES

YES

YES

YES

YES

YES

YES

NO

NO

N0

NO

NO

NO

NO

NO

N0

N0

NO

NO

NO

 

91

ANSWER SHEET

 

92

APPENDIX B

VALIDITY AND RELIABILITY OF THE TEST INSTRUMENT

93

APPENDIX B

VALIDITY AND RELIABILITY OF THE TEST INSTRUMENT
Part I——Test Instrument Validity
A fifteen item domain referenced test was developed
for this study and the validity and reliability' of the
instrument was established. Content validity was assessed
using the procedure presented by Mussio and Smith in

Content Validity: A Procedural Manual. The coefficient of

 

reliability of the instrument was established through a
pilot study.

In conducting the content validity assessment, four
traffic safety and traffic engineering experts were asked
to evaluate symbol signs on the basis of their importance
to the driving task. Each symbol sign was ranked on a
scale of l to 5 (high to low) and the average computed
from the four rankings. The fifteen symbol signs with the
highest rankings were selected for inclusion in the test
instrument as found in Appendix A. The rankings of the
fifteen selected items were subjected to statistical
analysis using a version of Kuder—Richardson Formula 20.
An index of interrater reliability and content validity of

r=.979 was established. Details are presented below.

941

Index of Interrater Reliability and Content Validity

l. Scores and Totals

TEST ITEMS
Raters l 2 3 4 5 6 7 8 9 10 ll 12 13 14 15 Rater Totals
#1 1 3 3 l 4 1 3 1 1 l l 1 1 l 1 24
#2 2 2 3 l 2 l 2 2 2 2 2 2 2 2 2 29
#3 2 2 l l 1 3 1 2 1 2 l 4 2 3 3 29
#4 l 1 1 l 1 3 3 3 3 3 3 1 3 l 1 29
Item Totals 6 8 8 4 8 8 9 8 7 8 7 8 8 7 7 111
Item Total 52 36 64 64 16 64 64 81 64 49 64 49 64 64 49 49 841
2. Squares of Scores and Totals
TEST ITEMS
Raters l 2 3 4 5 6 7 8 9 lo 11 12 l3 14 15 Totals
#1 1 9 9 1 16 l 9 l 1 l l 1 l 1 1 S76
#2 4 4 9 1 4 1 4 4 4 4 4 4 4 4 4 841
#3 4 4 1 1 1 9 1 4 1 4 1 l6 4 9 9 841
#4 1 1 1 l l 9 9 9 9 9 9 1 9 l 1 841

10 18 20 4 22 20 23 18 15 18 15 22 18 15 1S 3099

95

3. Sum of Squared Scores and Totals

Sum of Test Item Scores2 = 253

Sum of 15 Test Items Totals2 = 841

Sum of 4 Rater Totals2 = 3099

K(number of items) = 15

4. Variances

Sum of Items = 253 _ 841 = 13.129
15 152

Total Score = 3099 _ 1112 = 151.84
15 152

5. Interrater Reliability and Index of Content Validity

r = K [1 — f = 1 1 — 13.192 = .979
K—l , 4 151.84

<
w

<4
*‘I

The procedural manual prepared for the assessment of
content validity in developing the test instrument can be

found in Part III of this appendix.

Part II——Test Instrument Reliability

The reliability of the test instrument was established
through a pilot study in which the test was administered
to a random sample of fifty motor vehicle operator license
renewal applicants. Test results were tabulated and
subjected to statistical analysis using Kuder—Richardson
Formula 21' (K-R21'). A reliability correlation
coefficient of r=.945 was obtained. Details are presented

below.

96

The formula for the calculation was as follows:

K-RZI' = l — .8M (K-M) , where
sz

 

K = number of test items = 15

V = variance = 31.7556

M = mean test score = 12.38

r = 1 — [(.8)(12.38) (IS—12.38)] = l — .0545 = .9455

 

[(15)(31.7556)]

Part III——Content Validity Assessment Manual

97

CONTENT VALIDITY ASSESSMENT

FOR

A TEST OF NEW HAMPSHIRE DRIVERS’ KNOWLEDGE 0F SYMBOL SIGNS

C. GEORGE BONER
MAPLE LANE
SPOFFORO. NEW HAMPSHIRE 03462

(603)363-4329

 

98

INTRODUCTION

The obJective of this assessment is to establish the content
validity of a test instrument that will be used to determine
drivers’ knowledge of selected symbol signs. A secondary purpose
is to select a representative sample of Sign items, in each 04
the sign categories, to use in the construction of the
instrument.

RESEARCH OBJECTIVES

The purpose of this research is to:

1. Determine drivers’ familiarity with various symbol
signs.
2. Assess drivers’ knowledge 04 standardized symbol signs

that are used as traffic control deVices.

3. Distinguish between the ettects of the variables of age.
sex. driving experience. and formal training on knowledge 04
Symbol signs.

INSTRUCTIONS TO REVIENERS

Each of the steps in this content validity process is
outlined below. Please read through the sequence of steps and
then follow each in order. The process employed in this exercise
was developed by MUSSio and Smith and outlined in CONTENT
VALIDITY: A PROCEDURAL MANUAL.

The confidentiality of individual responses is guaranteed
and will only be reported as summary data in the final research
report. The reViewers should refrain from discussing their

assessment with one another during the content validity process
as independence is essential to the procedure.

1. ReView the description or the knowledge domain that will
be evaluated with the instrument being constructed. This is
a description of the skills and behaViors that are to be

tested in relation to the driVing task.

2. Provxde an assessment of the content areas which are
used to categorize the symbol signs. The categories
represent different tratfic sign clasSitications and are
widely accepted diVisions. In your assessment. you should

99

Page 3
answer the following question:

Do the listed content areas comprise relevant
categories of symbol signs?

3. Assign a weight to each of the symbol signs as to their
importance in the driVing task. One (1) represents the
highest ranking and five (5) the lowest.

4. Indicate which signs must tested in each category so
that there is a suffiCient number of items to discriminate
between drivers who do and do not have knowledge of the
category.

4. Rank each of the selected test items as:
I. Acceptable
2. Acceptable with reviSion
3

. Unacceptable

when assigning a ranking 0? 2. Acceptable with revision.
please indicate the necessary change(s).

5. Please provide comments as you feel appropriate.

6. Upon completion or the review. return the materials
promptly. An envelope is prov1ded tor your convenience.

 

 

100

Page 4

DESCRIPTION OF DOMAIN

The driver knowledge to be evaluated consists of:

l. The meaning that is perCieved as a result of seeing a
symbol sign.

2. The interpretation given to various symbolic messages 0‘
signs.

3. The knowledge of information relating to directions.
regulations. and conditions presented through Sign legends.

 

 

lOl

CONTENT VALIDITY ASSESSMENT

PART I EVALUATION OF CONTENT AREAS

The content areas defined for this study of knowledge of
Symbol signs conSist of the following sign class1fications:

1. Regulatory Signs

2. Warning signs

3. Guide signs

4. Information/service Signs
5. Construction Signs
RATING: (Please indicate with check mark)

Acceptable

 

Acceptable with reVisions

Unacceptable

Comments:

 

102

PART II SYMBOL SIGN EVALUATION
RELEVANCY SCALE FOR EVALUATION OF SYMBOL SIGNS

ASSign a weight to each of the following symbol signs
as to their importance in the performance of the driving
task. A range of 1 to 5 has been established with i being
the highest ranking and 5 being the lowest. Circle the
number representing your evaluation of the sign. The
following relevancy scale is provided as the basis for the
evaluation:

1 The driver must possess knowledge of this sign
to perform the driving task.

2

a Drivers possessing knowledge of this sign
should be able to perform the driving task at a
better than average level.

5

§ Drivers possesSing a knowledge of this sign

should be able to perform the driVing task at a
superior level.

REGULATOR» SIGNS

 

 

Note: The number following most Signs. i.e.(47l. is a reference
to the listing of the sign in the Manual on Unifcrm Traffic
Control DeVices — 1971.

1. NO RIGHT TURN (39) l 2 3 4 S

2. NO LEFT TURN <39) 1 2 3 4 5

3. NO U TURN (46) l 2 3 4 5

4. MANDATORY MOVEMENT (41) l 2 3 4 S

5. OPTIONAL MOVEMENT t4l) l 2 3 4 5

h]
(a)
A
Ul

KEEP RIGHT ‘45) 1

 

103

7. KEEP LEFT (46)
8. DO NOT ENTER (4?)
9. NO TRUCKS <48)

18. NO BICYCLES (49)

11. NO PARKING

12. CENTER LANE LEFT TURN ONLY

NARNING SIGNS

13. CURVE (66)

4. REVERSE TURN (66)

15. WINDING ROAD (66)

16. LARGE ARRON (68)

.—

7. CROSS ROAD ‘08)

18. SIDE ROAD (69)

19. T SYMBOL (69)

28. Y SYMBOL (o9)

21. SIGNAL AHEAD (71)

22. MERGE <72)

23. RIGHT LANE ENDS <72)
24. DIVIDED HIGHWAY (73)
25. DIVIDED HIGHWAY ENDS (74)
26. TWO-WAY TRAFFIC (75)
27. HILL (75)

28. SLIPPERY WHEN NET (77)
29. BICYCLE CROSSING (73)

38. PEDESTRIAN CROSSING (79)

Page
4 S
4 5
4 S
4 S
4 5
4 5
4 5
4 5
4 5
4 S
4 5
4 5
4 5
4 S
4 S
4 S
4 S
4 5
4 5
4 S
4 5
4 5
4 S
4 5

104

31. DEER CROSSING (79)
32. FARM MACHINERY <79)
33. DOUBLE ARROW (88)

34. LON CLEARANCE (88)
35. SCHOOL ADVANCE (327)
36. SCHOOL CROSSING (327)
37. STOP AHEAD

38. YIELD AHEAD

GUIDE SIGNS

39. ADVANCE TURN ARROW (96)

4%. DIRECTIONAL ARROW (96)

INFORMATION/SERVICE SIGNS

41. PICNIC TABLE (136)
42. TELEPHONE (189)
43. HOSPITAL (189)

44. CAMPING (118)

45. BIKE ROUTE (111)
46. HIKING TRAIL (112)
47. RESTAURANT

48. SERVICE STATION

49. LODGING

N

MN

Al

(Al

“I

(u

to

Page
4 5
4 S
4 5
4 S
4 5
4 5
4 5
4 5
4 5 '
4 5
4 S
4 5
4 5
4 5
4 S
4 5
4 5
4 5
4 5

105

Page 9

CONSTRUCTION SIGNS

Note: Construction Signs are referenced in work Zone Traffic
Control - April 1988. published by U.S. DOT/FHA.

58. ADVANCE FLAGGER (68-28) I 2 3 4 S
51. NARRON BRIDGE (68-22) 1 2 3 4 5
52. PAVEMENT ENDS (68-22) 1 2 3 4 5
53. WORKER AHEAD <68-21) 1 2 3 4 5
54. TWO-WAY TRAFFIC (68-21) 1 2 3 4 5
55. RIGHT LANE ENDS 1 2 3 4 5

106

PART III SELECTION OF SIGNS TO BE TESTED

Return to PART II and Circle the number of each Sign which
must be tested in order to discriminate between drivers who do
and those who do not have a knowledge of the signs within the
categories. Select the MINIMUM number of signs necessary to
evaluate the drivers’ knowledge in this domain.

PART IV RANKING OF SELECTED TEST ITEMS

Provide an evaluation of the test items corresponding to
the Signs Circled as requested in PART III. Test items relating
to Signs that were not Circled in PART 111 do not need to be
evaluated. '

Evaluate each of the test items using the following scale:

1. Acceptable

2. Acceptable with reviSions

3. Unacceptable

The necessary reVisions must be listed when ranking
number 2 is asSigned.

 

107

TEST ITEMS

1. " NO RIGHT TURN
THIS SIGN MEANS:

A NO TURNS
{8. NO RIGHT TURN
C NO RIGHT TURN ON RED

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING2 YES NO

RANKING: 1 2 3
COMMENTS:

NO LEFT TURN
THIS SIGN MEANS:

A. NO TURNS
8. LEFT TURNS PERMITTED
XC. NO LEFT TURN

 

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING7 YES NO

RANKING: I 2 3
COMMENTS:

3. 4' 7 WV NO U TURN
THIS SIGN MEANS:

A. NO TURN ON RED
. (8. NO U TURN
1 _1 c. U TURNS PERMITTED

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING’ YES NO

RANKING: 1 2 3
COMMENTS:

108

 

 

 

_____ Page 12
4. MANDATORY MOVEMENT
THIS SIGN MEANS:
1A. THE INDICATED TURN MUST BE MADE
0N LY a. NO TURNS ARE PERMITTED
c. THE LANE MAY BE USED TO MAKE A LEFT TURN

 

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES NO

RANKING: I 2 3
COMMENTS:

 

5. OPTIONAL MOVEMENT
THIS SIGN MEANS:

A. THE ROAD DIVIDES AHEAD
B. TRAFFIC MUST TURN LEFT

 

 

 

RHUE (GU EvER SEEN THIS SIGN WHILE DRIVING2 1E3 NO
RANKING: 1 2 3
COMMENTS:
a
l
o_ KEEP RIGHT

THIS SIGN MEANS:

A. LANE CLOSED AHEAD
i8. KEEP RIGHT OF AN OBSTRUCTION
—. C. TWO WAY TRAFFIC

 

 

HHvE YOU EVER SEEN THIS SIGN WHILE DRIVING° NO

"I
U!

RALFING: 1 2 3
COMMENTS:

w, , (C. THE LANE IS FOR LEFT TURNS OR THROUGH

TRAFFIC

109

 

 

:l Page 13
7. kEEP LEFT
THIS SIGN MEANS:
§A. kEEP LEFT OF AN DESTRUCTION
8. LANE CLOSED AHEAD
. . C. VEHICLES APPROACHING ON LEFT
HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING° YES NO
RANKING: I 2 3
COMMENTS:

DO NOT ENTER
THIS SIGN MEANS:

A. NO PARKING ANYTIME
*8. DO NOT ENTER THIS STREET OP ROAC
C. EXIT ONLY

 

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING2 YES NO

PHHYING: 1 2 3
COMMENTS:

9. 7" NO TRUCKS
THIS SIGN MEANS:

A. TRUCKS PERMITTED 3N STREETS ~ND ROADS
B. TRUCKS TURNING AT INTERSECTION
fC. NO TRUCKS ALLOWED

HA“F YOU EVER SEEN THIS SIGN WHILE DRIVING2 1E3 NO

RANKING: 1 2 3
COMMENTS:

110

NO BICYCLES
THIS SIGN MEANS:

XA. BICYCLE TRAFFIC

PROHIBITED

B. BICYCLE CROSSING AHEAD

— »— C. LANE FOR BICYCLES ONLY
HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING’ YES NO
RANKING: 1 2 3
COMMENTS:
II. NO PARKING
THIS SIGN MEANS:

A. PEGESTRIAN CROSSING PROHIBITED

f8. NO PARKING

C. NO PASSING
HAVE IOU EVER SEEN THIS SIGN WHILE DRIVING” YES NO
RANKING: I 2 3
COMMENTS:
12. CENTER LANE LEFT TLRN ONLY

THIS SIGN MEANS:

 

A. DIVIDED HIGHWAY

8. LEFT TURNS ONLI

iC. CENTER LANE FCQ
HAVE YOU EVER SEEN THIS SIGN WHILE DFIUING’
RANKING: l 2 3

COMMENTS:

AHEAD
AT INTERSECT I CNS

Lari C

111

Page

WARNING SIGNS

CURVE
UPON SEEING THIS SIGN A DRIVER SHOULD:

iA. SLOW AND PREPARE FOR A CURVE TO THE RIGHT
B. WATCH FOR TRAFFIC 0N SIDE ROADS
C. PROCEED AT A NORMAL SPEED

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING” YES NO

RANKING: 1 2 3
COMMENTS:

14. REVERSE TURN _
UPON SEEING THIS SIGN A DRIVER SHOULD:

A. E-PECT A DETOUR IN THE ROAD
i8. PREPARE FOR RIGHT CURVE THEN LEFT CURVE
C. STOP. THEN PROCEED WITH CAUTION

HAVE YOU EVER SEEN THIS SIGN WHILE DRI‘.‘IF\JC~:'> YES NO

RANKING: I 2 3
COMMENTS:

15. WINDING ROAD
UPON SEEING THIS SIGN A DRIVER SHOULD:

A. PROCEED AT A NORMAL SPEED
8. EXPECT A SERIES OF HILLS IN THE ROAD
(C. EXPECT A SERIES OF CURLES IN THE ROAD

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING7 YES NO

RANKING: I 2 3
COMMENTS:

15

 

112

LARGE ARROW
UPON SEEING THIS SIGN A DRIVER SHOULD:

(A. SLOW AND PREPARE TO MAKE A SHARP RIGHT TURN
B. EXPECT A SHARP LEFT TURN
C. E\PECT A CLOSED LANE AHEAD

II

 

 

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES NO

RANKING: 1
COMMENTS:

Ix!

3

CROSS ROAD
UPON SEEING THIS SIGN A DRIVER SHOULD:

A. E‘PECT A DIVIDED HIGHWAY
(B. WATCH FOR VEHICLES APPROCHING ON CROSSROAD
C. PREPARE TO MAKE A SERIES OF TURNS

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING9 YES NO

RANFING: I 2 3
COMMENTS:

SIDE ROAD
UPON SEEING THIS SIGN A DRIVER SHOULD:

A. PREPARE TO MAKE A LEFT TURN
8. STOP FOR ON-COMING TRAFFIC
1C. WATCH FOR VEHICLES APPROACHING ON SIDE RCHD

6

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING7

YES NO

RANKING: l 2 3
COMMENTS:

113

1?. T SYMBOL
UPON SEEING THIS SIGN A DRIVER SHOULD:

(A. PREPARE TO TURN LEFT OR RIGHT
B. PROCEED AT A NORMAL RATE OF SPEED
C. REDUCE SPEED AND PROCEED WITH CAUTION

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING7 YES NO

RANKING: l 2 3
COMMENTS:

28. Y SYMBOL
UPON SEEING THIS SIGN A DRIVER SHOULD:

A. SLOW AND PREPARE FOR A SERIES OF CURVES
(B. PREPARE TO TURN LEFT OR RIGHT
C. STOP FOR ON—COMING TRAFFIC

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING” YES NO

RANKING: 1
COMMENTS:

ILI

3

21. SIGNAL AHEAD
UPON SEEING THIS SIGN A DRIVER SHOULD:

PROCEED AT A NORMAL SPEED
SLOW AND PREPARE TO MAKE A RIGHT '.:M
PREPARE TO STOP IF SIGNAL IS REL

FICUD

l

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING7 YES NO

RANKING: 1 2 3
COMMENTS:

114

Page 18

22. MERGE
UPON SEEING THIS SIGN A DRIVER SHOULD:

lA. WATCH FOR TRAFFIC ENTERING FROM RIGHT
8. SLOW AND PREPARE TO STOP
C. PREPARE TO MERGE WITH TRAFFIC

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING° YES NO

RANKING: I 2 3
COMMENTS:

23. RIGHT LANE ENDS
UPON SEEING THIS SIGN A DRIVER SHOULD:

A. WATCH FOR ON-COMING 'RAFFIC
X8. MERGE LEFT IF TRAVELLING IN RIGHT LANE
C. PREPARE FOR A SERIES OF CURVES

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING’ YES NO

RANKING: 1 2 3
COMMENTS:

24. DIVIDED HIGHWAY
UPON SEEING THIS SIGN A DRIVER SHOULD:

A. PREPARE FOR TWO-WAY TRAFFIC AHEAD
8. MOVE RIGHT TO AVOID A HAZARD

(C. EXPECT A DIVIDED HIGHWAY AHEAD
HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING7 vES NO

RANKING: I 2 3
COMMENTS:

 

115

Page 19
25. DIVIDED HIGHWAY ENDS
UPON SEEING THIS SIGN A DRIVER SHOULD:

XA. EXPECT THE END OF A DIVIDED HIGHWAY
8. MOVE RIGHT TO AVIOD A HAZARD
C. ExPECT A DIVIDED HIGHWAY AHEAD

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING” YES NO

RANKING: I 2 3
C OMMENTS :

26. TWO-WAY TRAFFIC
UPON SEEING THIS SIGN A DRIVER SHOULD:

A. PREPARE FOR A DIVIDED ROADWAY AHEAD
QB. EXPECT A TWO-WAY ROADWAY AHEAD

L. WATCH FOR MERGING TRAFFIC
HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING7 YES NO

RANKING: l 2 3
COMMENTS:

HILL
UPON SEEING THIS SIGN A DRIVER SHOULD:

A. AATCH FOR TRUCKS CROSSING AHEAD
B. WATCH FOR STOPPED VEHICLES
iC. REDUCE SPEED AND PREPARE FOR A DOWN—GRADE

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING° YES NC

RANKING: I 2 3
COMMENTS:

116

Page 28
28. SLIPPERY WHEN WET
UPON SEEING THIS SIGN A DRIVER SHOULD:

1A. PREPARE FOR SLIPPERY ROAD IF SURFACE IS WET
B. EXPECT A HIGHWAY FOR CARS ONLY
C. REDUCE SPEED AND PREPARE FOR A SERIES OF TURNS

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING° YES NO

RANKING: 1 2 3
COMMENTS:

BICYCLE CROSSING
UPON SEEING THIS SIGN A DRIVER SHOULD:

29.

A. KEEP OUT OF BICYCLE LANE
(B. WATCH FOR BICYCLE CROSSING OR TRAFFIC
C. YIELD RIGHT OF WAY TO BICYCLES

 

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES NO

RANKING: I 2 3
COMMENTS:

38. PEDESTRIAN CROSSING
UPON SEEING THIS SIGN A DRIVER SHOULD:

WATCH FOR SCHOOL CROSSING AHEAD
HITCH HIKING PROHIBITED
. WATCH FOR PEDESTRIAN CROSSING AHEAD

DMD

R
HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING’ YES NO

RANKING: I 2
COMMENTS:

117

Page 21

31. DEER CROSSING
UPON SEEING THIS SIGN A DRIVER SHOULD:

XA. WATCH FOR DEER CROSSING THE ROADWAY
B. WATCH FOR CATTLE CROSSING AHEAD
C. WATCH FOR WILDLIFE PRESERVE AHEAD

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES NO

RANKING: 1 2 3
COMMENTS:

FARM MACHINERY
A. WATCH FOR MAINTENANCE WORK AHEAD'
B. PREPARE TO STOP
XC. WATCH FOR FARM MACHINERY ON ROADWAY

32.

 

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES NO

RANKING: I 2 3
COMMENTS:

33. DOUBLE ARROW
UPON SEEING THIS SIGN A DRIVER SHOULD:

XA. PREPARE TO PASS ON EITHER SIDE OF A HAZARD
B. KEEP RIGHT
C. REDUCE SPEED AND PREPARE TO STOP

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES NO

RANKING: 1 2 3
COMMENTS:

118

Page 22
34. LOW CLEARANCE
UPON SEEING THIS SIGN A DRIVER SHOULD:

A. EXPECT PAVEMENT TO NARROW TO 12 FEET 6 INCHES
X8. EXPECT A LOW CLEARANCE OF 12 FEET 6 INCHES
C. USE PARKING SPACES 12 FEET 6 INCHES LONG

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES NO

RANKING: I 2 3
COMMENTS:

SCHOOL ADVANCE
UPON SEEING THIS SIGN A DRIVER SHOULD:

35.

A. WATCH FOR CROSSING FOR THE BLIND
B. PREPARE TO ENTER A HEAVILY POPULATED AREA
(C. PREPARE TO ENTER A SCHOOL ZONE

 

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES NO

RANKING: I 2 3
COMMENTS:

SCHOOL CROSSING
UPON SEEING THIS SIGN A DRIVER SHOULD:

36.

1A. WATCH FOR CHILDREN CROSSING THE STREET
8. WATCH FOR A CRCSSING FOR T~E 1““
C. PREPARE TO ENTER A PECES'RIAN IRIESIKO AREA

 

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES NU

RANKING: 1 2 3
COMMENTS:

 

 

119

37. STOP AHEAD
UPON SEEING THIS SIGN A DRIVER SHOULD:

A. EXPECT ON-COMING TRAFFIC TO STOP AT INTERSECTICN

kB. REDUCE SPEED AND PREPARE TO STOP
C. NOT TURN RIGHT AT INTERSECTION

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES NO

RANKING: I 2 3
COMMENTS:
38. YIELD AHEAD
. UPON SEEING THIS SIGN A DRIVER SHOULD:
A. NOT TURN LEFT AT INTERSECTION
8. EXPECT ON-COMING TRAFFIC TO STOP
1C. REDUCE SPEED AND PREPaRE TO STOP IF NEIESS-RY

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES NO

RANKING: I 2 3
COMMENTS:

GUIDE SIGNS
39. ADVANCE TURN ARROW

THIS SIGN MEANS:

!A. THE ROUTE BEING TRAVELLED TURNS LEFT AHEAD
E. CENTER LANE LEFT TURN ONLY
C. ALL TRAFFIC MUST TURN LEFT

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING” '35 NO

RANKING: 1 2 3

COMMENTS:

120

Page 24

48. DIRECTIONAL ARROW
THIS SIGN MEANS:

I A. NO TURNS PERMITTED

{8. THE ROUTE BEING FOLLOWED PROCEEDS STRAIGHT
C. ALL TRAFFIC MUST GO STRAIGHT

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES NO

RANKING: I 2 3
COMMENTS:

INFORMATION SERVICE SIGNS
41. PICNIC TABLE

THIS SIGN MEANS:

f¥,, A. REST AREA
8. CAMPING AREA AHEAD
xc. ROADSIDE PIZNIC TABLE AHEAD
HAVE YOU EVER SEEN THIS SIGN WHILE 3RIHIHG° ~E3 <0
RANKING: l 2 3
CIMMENTS:
42. TELEPHONE

THIS SIGN MEANS:

(A. ROADSIDE TELEPHONE AHEAD
8. EMERGENCY SERVICE AREA
C. END OF EMERGENCY TELEPHONE NETWCRK

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING’ YES NO

RANKING: l 2 3
C OMMENTS :

121

43. HOSPITAL
THIS SIGN MEANS:

A. HOTEL PARKING
(8. DIRECTION TO HOSPITAL
C. LODGING INFORMATION

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES

RANKING: I A 3
COMMENTS:

44, CAMPING
THIS SIGN MEANS:

A LODGING INFORMATION

A.

e. PEST AREA
xc. CAMPING AREA
HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES

RANKING: I 2 3
COMMENTS:

45. BIKE ROUTE
THIS SIGN MEANS:

    

BEEIEEE, IA. BICYCLE ROUTE
9. NO BICYCLES
c.

BICYCLE CROSSING AHEAD
HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? (ES

RANK I HG: I 2 3
COMMENTS:

NO

NO

NO

Page

25

122

Page

HIKING TRAIL
THIS SIGN MEANS:

A. PEDESTRIAN CROSSING
i8. HIKING TRAIL
C. SCHOOL ZONE

 

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES NO

RANKING: I 2 3
COMMENTS:

47. RESTAURANT
THIS SIGN MEANS:

A. LODGING INFORMATION
8. PICNIC AREA
iC. RESTAURANT OR DINING FACILITY

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES NO

RANKING: I 2 3
COMMENTS:

48. SERVICE STATION
THIS SIGN MEANS:

i (A. SERVICE STATION

B. REST AREA
C TRAVEL INFORMATION

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES NO

RANKING: 1 2 3
COMMENTS:

26

 

 

123

49. LODGING

THIS SIGN MEANS:
I.-.
A. REST AREA
18. LODGING OR MOTEL SERVICES
C. TRAVEL INFORMATION

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES

RANKING: I 2 3
COMMENTS:

CONSTRLCTIZN SIGNS
58. ADVANCE FLAGGER

THIS SIGN MEANS:

MEN WORKING
DETOUR AHEAD
FLAGMAN AHEAD

(”AIDD

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES

RANKING: I 2 3
COMMENTS:

SI. NARROW BRIDGE
THIS SIGN MEANS:

iA. NARROW BRIDGE AHEAD
B. OBSTRUCTION IN ROADWAY
C. SOFT SHOULDER

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES

RANKING: I 2 3
COMMENTS:

NO

NO

NO

124

52. PAVEMENT ENDS
THIS SIGN MEANS:

 

A. BUMP
XB. PAVEMENT ENDS
C. ROAD NARROWS

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES

RANKING: I 2 3
COMMENTS:

53. WORKER
THIS SIGN MEANS:

A. FLAGMAN AHEAD
B. ROAD MACHINERY AHEAD
*C. WORKERS IN ROADWAY

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES

RANKING: 1
COMMENTS:

3

h]

  
 

\ TWO-WAY TRAFFIC
“THIS SIGN MEANS:

iA. TWO-WAY TRAFFIC AHEAD
8. STOP FOR ON-COMING TRAFFIC
C. DIVIDED HIGHWAY AHEAD

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES

RANKING: I 2 3
COMMENTS:

NO

NO

NO

m” ."‘m‘1s““‘;

gr, '. . ’

 

55.

125

RIGHT LANE ENDS
THIS SIGN MEANS:

A. NO TURNS
*8. ROAD NARROWS FROM RIGHT
C. TWO-WAY ROADWAY AHEAD

HAVE YOU EVER SEEN THIS SIGN WHILE DRIVING? YES NO

RANKING: I 2 3

COMMENTS:

126

APPENDIX C

READABILITY ASSESSMENT OF THE TEST INSTRUMENT

127

Keene State College

Inter—Department Memorandum
To: George Bower

Dam: October 20. 1982
Front Glenna Mize, Ph.D.

Reading Specialist - Safety Center

Using the Frye Readability Formula attached, the estimated average
reading difficulty of the three-page form is 4.2.

Page Sentences Syllables Estimated Grade Level
1 9 133 5.3

2 8 117 3

3 8 115 3

A 7.5 125 5.5

11.5 f 4 - 4.2
The addition of the sign should reduce the reading difficulty even
more because of the visual representation.

GJM:jb

128

APPENDIX D

ANALYSIS TABLES OF THE TEST VARIABLES

129

Tab1e 01

Mean Scores of Test Subjects by Age and Sex

 

BREAKDOWN OF AGE AND SEX

ACROSS - AGE
DOWN - SEX
Age Groups
16-19 20—29 30-39 40—49 50-59 60-69 70+ TOTAL
FEMALE
MEAN 85.000 78.000 82.686 77.706 63.667 64.700 71.000 : 76.404
STDOEV 8.485 19.494 9.489 11.537 12.698 16.125 17.088 1 15.538
N 4 30 35 17 15 10 3 : 114
HALE
MEAN 87.000 82.880 84.222 82.650 75.063 77.400 77.667 : 81.571
STDOEV .000 11.319 11.804 15.618 20.407 11.327 4.041 : 14.087
N 2 25 27 20 16 5 3 98
TOTAL
MEAN 85.667 80.218 83.355 80.378 69.548 68.933 74.333 1 78.792
STDOEV 6.653 16.341 10.496 13.933 17.804 15.563 11.690 1 15.073

N 6 55 62 37 31 1S 6 : 212

 

Tab1e 02

Mean Scores of Test Subjects by Age and Training

 

ACROSS — AGE

DOWN -TRA1NING - DRIVER EDUCATION

20—29

76.333

27.717

80.978

13.425

50-59

69.920
17.888

25

68.000

19.037

60-69

68.933
15.563

15

0

70+

78.600

5.857

53.000

.000

TOTAL

16—19

NO TRAINING 0
0

0

TRAINING 85.667
6.653

6

TOTAL 85.667
6.653

6

AGE GROUPS

30-39 40-49
81.708 77.739
12.376 15.789
24 23
84.395 84.714
9.140 9.118
38 14
83.355 80.378
10.496 13.933
62 37

69.548
17.804

31

74.333

11.690

 

 

131

Table 03

Mean Scores of Test Subjects by Driving Experience and Sex

 

BREAKDOWN OF EXPERIENCE AND SEX
ACROSS - EXPERIENCE

DOWN - SEX

DRIVING EXPERIENCE CLASSIFICATIONS (MILES PER WEEK)

1 . 2. 3. 4. 5. 6. 7. 8. TOTAL

FEMALE
MEAN 73.500 69.400 77.279 75.214 78.211 80.700 73.500 : 76.404
STDDEV 9.192 16.426 13.539 20.565 15.175 8.015 9.192 : 15.538
N 2 10 43 28 19 10 2 0 : 114

MALE

MEAN 66.667 77.091 81.688 80.273 80.700 89.000 87.765 : 81.571
STDDEV 34.962 17.207 13.446 12.464 12.374 3.464 10.680 : 14.087
N 0 3 11 32 22 10 3 17 98
TOTAL 73.500 68.769 77.241 78.667 79.317 80.700 82.800 87.765 2 78.792
9.192 20.187 14.182 17.296 13.648 10.147 9.960 10.680 2 15.073
2 13 54 6O 41 20 5 17 : 212

Driving Experience CTassifications in Hi1es per Heek

1. 0 2. 1-20
2. 20-50 3. 50-100
5. 100-200 6. 200-300

7. 300—400 8. 400+

 

".I.‘ --- :-

 

132

TabTe 04

Mean Scores of Test Subjects by Experience and Training

 

BREAKDOWN OF EXPERIENCE AND TRAINING
ACROSS — EXPERIENCE

DOWN - TRAINING - DRIVER EDUCATION

EXPERIENCE CLASSIFICATIONS IN MILES PER WEEK'

1. 2. 3. 4. 5. 6. 7. 8. TOTAL
NO TRAINING
MEAN 67.000 60.200 75.333 73.971 75.643 77.778 80.250 84.000 : 75.356
STDDEV .000 22.163 14.893 20.126 17.310 12.091 9.430 10.187 : 16.994
N 1 5 24 34 14 9 4 1O : 101
TRAINING
MEAN 80.000 74.125 78.767 84.808 81.222 83.091 93.000 93.143 : 81.919
STDDEV .000 18.240 13.647 10.104 11.212 8.043 .000 9.547 2 12.352
N 1 8 30 26 27 11 1 7 111
TOTAL
MEAN 73.500 68.769 77.241 78.667 79.317 80.700 82.800 87.765 : 78.792
STDDEV 9.192 20.187 14.182 17.296 13.648 10.147 9.960 10.680 : 15.073
N 2 13 54 60 41 20 5 17 : 212

'Driving Experience C1assifications in Mi1es per Heek

1. 0 2. 1—20
2. 20-50 3. 50-100
5. 100—200 6. 200-300

7. 300—400 8. 400+

 

133

Table D5

Mean Scores of Test Subjects by Sex and Training

 

BREAKDOWN OF SEX AND TRAINING
ACROSS - SEX
DOWN - TRAINING - DRIVER EDUCATION

FEMALE MALE
NO TRAINING
MEAN 72.865 78.000 75.356
STDDEV 17.255 16.476 16.994
N 52 49 101
TRAINING
MEAN 79.371 85.143 81.919
SDTDEV 13.368 10.176 12.352
N 62 49 111
TOTAL
MEAN 76.404 81.571 78.792
STDDEV 15.538 14.087 15.073

N 114 98 212

 

134

Table D6

Correlation Matrix for Test Variables

 

NUMBER OF CASES = 212

CORRELATION, SIGNIFICANCE

AGE -.272
.000
SEX .171 .022
.006 .374
TRAINING .218 -.541 -.044
.001 .000 .263
EXPERIENCE .226 -.047 .393 -.059
.000 .250 .000 .198

KNOWLEDGE AGE SEX TRAINING

 

135

APPENDIX E

BREAKDOWN OF TEST ITEM RESPONSES

Table E—l

Item 1: No Left Turn

 

 

 

1. THIS SIGN MEANS:
A. NO TURNS
B. LEFT TURNS ALLOWED
C. NO LEFT TURNS ALLOWED
RESPONSE N TOT % NM % CUM %
A 18 8.5 8.6 8.6
B 10 4.7 4.8 13.4
C 181 85 4 86.6 100.0 CORRECT
0 3 l 4 NA NA NO RESPONSE
RESPONSES TO ITEM 1 = 209

"Have you ever seen this sign while driving?"

YES:

187 (88.7%) NO: 22 NO RESPONSE:

Number of Responses
% of All Responses

0

a of Valid Responses

0

Cumulative s

3

 

137

Table E-2

Item 2: Right Turn Only

 

2. THIS SIGN MEANS:

A. THE INDICATED TURN MUST BE MADE
B. NO TURNS ARE ALLOWED
C. THE LANE MAY BE USED TO MAKE A LEFT TURN

 

 

RESPONSE N TOT % NM % CUM % LABEL
A 126 59.4 60.0 60.0 CORRECT
B 1 .5 5 60.5
C 83 39.2 39 5 100.0
0 2 .9 NA NA NO RESPONSE

RESPONSES TO ITEM 2 = 210

"Have you ever seen this sign while driving?"

YES: 199 (93.8%) NO: 9 NO RESPONSE: 4

N = Number of Responses
TOT % = % of All Responses

% of Valid Responses
CUM % = Cumulative %

 

 

138

Table E—3

Item 3: Keep Left

 

3. THIS SIGN MEANS:
A. KEEP LEFT
B. LANE CLOSED AHEAD
C. VEHICLE APPROACHING ON LEFT

 

 

RESPONSE N TOT % NM % CUM % LABEL
A 178 84.0 87.7 87.7 CORRECT
B 20 9.4 9.9 97.5
C 5 2.4 2.5 100.0
0 9 4.2M NA NA NO RESPONSE

RESPONSES TO ITEM 3 = 203

"Have you ever seen this sign while driving?"

YES: 128 (63.4%) NO: 79 NO RESPONSE: 5
N = Number of Responses
TOT % = % of All Responses
NM% = % of Valid Responses

0

Cumulative a

o\°
II

CUM

 

Table E—4

Item 4: Do Not Enter

 

 

 

4. THIS SIGN MEANS:
A. NO PARKING ANYTIME
B. DO NOT ENTER THIS STREET OR ROAD
C. EXIT ONLY
RESPONSE N TOT % NM % CUM %

A 5 2 4 2.4 2.4

B 200 94 3 95.2 97.6 CORRECT

C 5 2 4 2.4 100.0

OM 2M 9M NA NA NO RESPONSE

RESPONSES TO ITEM 4 = 210

"Have you ever seen this sign while driving?"

YES: 205 (96.7%) NO: 4 NO RESPONSE: 3
N = Number of Responses
TOT % = % of All Responses
NM% = of Valid Responses

CUM % = Cumulative %

 

140

Table E—5

Item 5: Center Lane Left Turn Only

 

THIS SIGN MEANS:

 

 

A. DIVIDED HIGHWAY AHEAD
B. LEFT TURNS ONLY AT INTERSECTION
C. CENTER LANE FOR LEFT TURNS ONLY
RESPONSE N TOT % NM % CUM %
A 23 10.8 12.4 12.4
B 102 48.1 54.8 67.2
C 61 28.8 32.8 100.0 CORRECT
OM 26M 12.3M NA

RESPONSES TO ITEM 5 = 186

"Have you ever seen this sign while driving?"

TOT
NM%
CUM

o\°

o\°

YES:

49 (23.1%) NO: 161

NO RESPONSE:

Number of Responses
% of All Responses

% of Valid Responses

Cumulative %

NA NO RESPONSE

2

 

 

141

Table E—6

Item 6: Right Curve

 

 

 

6. UPON SEEING THIS SIGN A DRIVER SHOULD:
A. SLOW AND LOOK FOR RIGHT CURVE
B. WATCH FOR TRAFFIC ON SIDE ROADS
C. PROCEED AT NORMAL SPEED
RESPONSE N TOT % NM % CUM %

A 200 94.3 94.3 94.3 CORRECT

B 3 1.4 1.4 95.8

C 9 4.2 4.2 100.0

RESPONSES TO ITEM 6 = 212

"Have you ever seen this sign while driving?"

YES: 206 (97.2%) NO: 6 NO RESPONSE: 0
N = Number of Responses
TOT % = % of All Responses
NM% = % of Valid Responses
CUM % = Cumulative %

 

142

Table E—7

Item 7: T Intersection

 

 

 

7. UPON SEEING THIS SIGN A DRIVER SHOULD:
A. PREPARE TO TURN LEFT OR RIGHT
B. DRIVE AT A SAFE SPEED
C. REDUCE SPEED AND DRIVE WITH CARE
RESPONSE N TOT % NM % CUM %

A 170 80.2 86.3 86.3 CORRECT

B 4 1.9 2.0 88.3

C 23 10.8 11.7 100.0

0 15 7.1 NA NA NO RESPONSE

RESPONSES TO ITEM 7 = 197

"Have you ever seen this sign while driving?"

YES: 117 (55.2%) NO: 93 NO RESPONSE: 2
N = Number of Responses
TOT % = % of All Responses
NM% = % of Valid Responses

CUM % = Cumulative %

 

 

143

Table E—8

Item 8: Merging Traffic

 

8. UPON SEEING THIS SIGN A DRIVER SHOULD:

A. WATCH FOR TRAFFIC ENTERING FROM RIGHT
B. PREPARE TO STOP
C. MERGE WITH TRAFFIC

 

 

RESPONSE N TOT % NM % CUM %
A 175 82.5 83.7 83.7 CORRECT
B 1 .5 .5 84.2
C 33 15.6 15.8 100.0
0 3 1.4 NA NA NO RESPONSE

RESPONSES TO ITEM 8 = 209

"Have you ever seen this sign while driving?"

YES: 173 (81.6%) NO: 35 NO RESPONSE: 4
N = Number of Responses
TOT % = % of All Responses
NM% = % of Valid Responses

CUM % = Cumulative %

 

144

Table E—9

Item 9: Merge Left

 

 

 

9. UPON SEEING THIS SIGN A DRIVER SHOULD:
A. WATCH FOR ONCOMING TRAFFIC
B. MERGE LEFT
C. WATCH FOR LOW SHOULDER
RESPONSE N TOT % NM % CUM %

A 31 14.6 15.2 15.2

B 152 71.7 74.5 89.7 CORRECT

C 21 9.9 10.3 100.0

0 8 3.8 NA NA NO RESPONSE

RESPONSES TO ITEM 9 204

"Have you ever seen this sign while driving?"

YES: 149 (70.3%) NO: 57 NO RESPONSE: 6
N = Number of Responses
TOT % = % of All Responses

NM% - % of Valid Responses
CUM °

Cumulative s

o\°
1|

 

145

Table E-lO

Item 10: Divided Highway Ahead

 

 

 

10. UPON SEEING THIS SIGN A DRIVER SHOULD:
A. LOOK FOR TWO WAY TRAFFIC AHEAD
B. MOVE RIGHT TO AVOID OBSTRUCTION
C. EXPECT A DIVIDED HIGHWAY
RESPONSE N TOT % NM % CUM %
A 20 9.4 10.0 10.0
B 30 14.2 15.0 25.0
C 150 70.8 75.0 100.0 CORRECT
O 12 5.7 NA NA NO RESPONSE
RESPONSES TO ITEM 10 = 200

"Have you ever seen this sign while driving?"

YES:

129 (60.8%) NO: 78 NO RESPONSE: 5

Number of Responses

0

s of All Responses

6 of Valid Responses
Cumulative %

 

 

146

Table E-ll

Item 11: Slippery Road

 

 

 

11. UPON SEEING THIS SIGN A DRIVER SHOULD:
A. LOOK FOR WET SLIPPERY ROAD
B. EXPECT A ROAD FOR CARS ONLY
C. LOOK FOR A SERIES OF CURVES
RESPONSE N TOT % NM % CUM %

A 193 91.0 92.8 92.8 CORRECT

B 1 .5 .5 93.3

C 14 6.6 6.7 100.0

0 4 1.9 NA NA NO RESPONSE

RESPONSES TO ITEM 11 = 208

"Have you ever seen this sign while driving?"

YES: 178 (84.0%) NO: 21 NO RESPONSE: 4
N = Number of Responses
TOT % = % of All Responses
NM% = of Valid Responses

0

%
Cumulative 6

('3
C.‘
3
o\°
11

 

 

147

Table E-12

Item 12: Low Clearance — 12 Feet 6 Inches

 

12. UPON SEEING THIS SIGN A DRIVER SHOULD:

EXPECT ROAD TO NARROW TO 12 FEET 6 INCHES
EXPECT LOW CLEARANCE OF 12 FEET 6 INCHES
USE PARKING SPACES 12 FEET 6 INCHES

noo>

 

RESPONSE N TOT % NM % CUM %

 

2.9 2.9
100.0 CORRECT
NA NA NO RESPONSE

otbfi’
N
o
N
KO

rewim

tooim
o
q
H

RESPONSES TO ITEM 12 = 208

"Have you ever seen this sign while driving?"

YES: 191 (90.1%) NO: 18 NO RESPONSE: 3

Z
11

Number of Responses
TOT % % of All Responses

NM% % of Valid Responses
CUM %

0

Cumulative a

 

 

'A\

 

148

Table E—13

Item 13: Narrow Bridge

 

 

 

13. THIS SIGN MEANS:
A. NARROW BRIDGE
B. OBSTRUCTION IN ROAD
C. SOFT SHOULDER
RESPONSE N TOT % NM % CUM %

A 176 83.0 92.6 92.6 CORRECT

B 7 3.3 3.7 96.3

C 7 3.3 3.7 100.0

0 22 10.4 NA NA NO RESPONSE

RESPONSES TO ITEM 13 = 190

"Have you ever seen this sign while driving?"

YES: 48 (22.6%) NO: 158 NO RESPONSE: 6
N = Number of Responses
TOT % = % of All Responses

NM% % of Valid Responses
CUM % = Cumulative %

 

149

Table E—l4

Item 14: Workers On Road

 

 

 

14. THIS SIGN MEANS:
A. FLAGMAN AHEAD
B. ROAD WORK
C. WORKERS ON ROAD
RESPONSE N TOT % NM % CUM %

A 33 15.6 16.2 16.2

B 39 18.4 19.1 35.3

C 132 62.3 64.7 100.0 CORRECT

0 8 3.8 NA NA NO RESPONSE

RESPONSES TO ITEM 14 = 204

"Have you ever seen this sign while driving?"

YES: 98 (46.2%) NO: 109 NO RESPONSE: 5
N = Number of Responses
TOT % = % of All Responses
NM% = % of Valid Responses
CUM % = Cumulative %

 

150

Table E-lS

Item 15: Two Way Traffic

 

 

15. THIS SIGN MEANS:
A. TWO-WAY TRAFFIC
B. STOP FOR ON-COMING TRAFFIC
C. DIVIDED ROAD
RESPONSE N TOT % NM % CUM %

 

208 98.1 98.1 98.1 CORRECT
4 1.9 1.9 100.0

03>

RESPONSES TO ITEM 14 = 212

"Have you ever seen this sign while driving?"

TOT
NM%
CUM

o\°

YES: 176 (83.0%) NO: 31 NO RESPONSE:

= Number of Responses
% of All Responses
% of Valid Responses

Cumulative %

 

 

AAAAAAAAAAAAAAAAA

‘1“111.111111611111111111‘3

30

 

“111111

293