The Effects of Commercial Electronic Variable Message Signs ...

TABLE OF CONTENTS
1.0 INTRODUCTION................................................................................................................... 1
1.1 BASIC RESEARCH QUESTION................................................................................... 1
1.2 SCOPE ............................................................................................................................... 2
2.0 LITERATURE REVIEW UPDATE..................................................................................... 5
2.1 BACKGROUND ............................................................................................................... 5
2.2 POST-HOC CRASH STUDIES ...................................................................................... 5
2.3 FIELD INVESTIGATIONS ............................................................................................ 6
2.4 LABORATORY INVESTIGATIONS............................................................................ 9
2.5 PREVIOUS LITERATURE REVIEWS....................................................................... 11
2.6 REVIEWS OF PRACTICE ........................................................................................... 13
2.7 CONCLUSIONS FROM LITERATURE REVIEW................................................... 14
2.7.1 Basic Research Question.......................................................................................... 14
2.7.2 Methodological Implications ................................................................................... 16
3.0 KEY FACTORS AND MEASURES................................................................................... 19
3.1 KEY FACTORS (INDEPENDENT VARIABLES)..................................................... 19
3.2 KEY MEASURES (DEPENDENT VARIABLES)...................................................... 22
4.0 RESEARCH STRATEGIES................................................................................................ 25
5.0 FUTURE RESEARCH PROGRAM................................................................................... 29
5.1 STAGES........................................................................................................................... 29
5.2 APPROACH....................................................................................................................30
5.3 STRUCTURE.................................................................................................................. 31
5.3.1 Stage 1—Determination of Distraction ................................................................... 31
5.3.2 Stage 2—Basis for Regulation................................................................................. 31
5.3.3 Stage 3—Relationship to Crashes............................................................................ 32
6.0 RECOMMENDED FIRST STAGE STUDY ..................................................................... 35
6.1 SUMMARY OF STUDY APPROACHES.................................................................... 35
6.1.1 On-Road Instrumented Vehicle ............................................................................... 35
6.1.2 Naturalistic Driving ................................................................................................. 36
6.1.3 Unobtrusive Observation ......................................................................................... 36
6.2 COMPARISON OF STUDY ALTERNATIVES ......................................................... 37
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