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21st Century Operations Using 21st Century Technologies

Synthesis of Variable Speed Limit Signs

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United States Department of Transportation Federal Highway Administration

U.S. Department of Transportation
Federal Highway Administration
Office of Operations
1200 New Jersey Avenue, SE
Washington, DC 20590

FHWA-HOP-17-003

May 2017


Table of Contents

[ Foreword ] [ Notice and Quality Assurance Statement ] [ Technical Report Documentation Page ] [ SI Conversions ] [ Acronyms ]

EXECUTIVE SUMMARY
CHAPTER 1. INTRODUCTION
SHORT DESCRIPTION
HISTORY AND PREVIOUS RESEARCH
CHAPTER 2. RESEARCH METHODOLOGY
LITERATURE REVIEW
AGENCY OUTREACH
SYNTHESIS AND ANALYSIS
CHAPTER 3. VARIABLE SPEED LIMIT STATE OF THE PRACTICE
REPRESENTATIVE VARIABLE SPEED LIMIT SYSTEMS IN THE UNITED STATES
VARIABLE SPEED LIMIT SYSTEMS USED FOR CONTESTION-BASED ACTIVE TRAFFIC MANAGEMENT
VARIABLE SPEED LIMIT SYSTEMS USED FOR WORK ZONES
VARIABLE SPEED LIMIT SYSTEMS USED FOR WEATHER
DEACTIVATED VARIABLE SPEED LIMIT SYSTEMS IN THE UNITED STATES
LESSONS LEARNED
CHAPTER 4. FINDINGS
PLANNING AND POLICY
DESIGN, DEPLOYMENT, AND STANDARDS
OPERATIONS AND MAINTENANCE
OUTCOMES
CHAPTER 5. CONCLUSION - BENEFITS AND CHALLENGES OF VARIABLE SPEED LIMIT SYSTEMS
KEY BENEFITS
KEY CHALLENGES
VARIABLE SPEED LIMIT KEY CONSIDERATIONS
FUTURE OF VARIABLE SPEED LIMITS
APPENDIX A. BIBLIOGRAPHY
APPENDIX B. AGENCY INTERVIEW SUMMARY

List of Figures

Figure 1 Photo. New Jersey Turnpike variable speed limit and variable message signing
Figure 2 Figure 2. Chart. Weather responsive system for OR 217

List of Tables

Table 1 Summary of variable speed limit data sources
Table 2 Description of the variable speed limit systems considered in the report
Table 3 Lessons learned by State agencies from variable speed limit implementations
Table 4 Fundamental variable speed limit infrastructure requirements
Table 5 Washington State Department of Transportation speed limit reference
Table 6 Variable speed limit system practices and field results
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