Road safety

Cover of Best Practice for Variable Speed Limits: Best Practice Recommendations
Best Practice for Variable Speed Limits: Best Practice Recommendations
  • Publication no: AP-R344-09
  • ISBN: 978-1-921551-72-7
  • Published: 20 October 2009

Austroads project NS1378 Best Practice for Variable Speed Limits (VSL) aims to review international and domestic VSL initiatives, recommend methods to achieve best practices in VSL design and operational issues, propose a consistent appearance so motorists can travel around Australasia and understand the VSL system, share knowledge among practitioners and encourage consistent VSL applications across jurisdictions.

This report is the third deliverable of the project and provides best practice recommendations in VSL design and operational principles. This report was developed following consultation with practitioners, a comprehensive literature review (Han et al. 2008) and a user comprehension study conducted in four capital cities (Pyta & Han 2008).

  • Project Manager
  • 1. INTRODUCTION
    • 1.1. Background
    • 1.2. Findings from Literature Review and User Comprehension and Perception Study
    • 1.3. Contents of the Report
  • 2. VSL OPERATIONAL PRINCIPLES
    • 2.1. Purposes of VSL Installation
    • 2.2. Definition of VSL
    • 2.3. Mode of Operation
    • 2.4. General Principles of Speed Changes
    • 2.5. Sign Failure
    • 2.6. Communicating and Highlighting Speed Changes
  • Variable speed limit (VSL)
  • Variable speed limit zone
  • Variable speed limit sign
  • Variable speed limit system
  • Time-of-day
  • Dynamic speed limits
  • Manual intervention
  • Manual control
  • 3. SIGNAGE DISPLAY AND PLACEMENT
    • 3.1. Sign Size
    • 3.2. Signage Placement
    • 3.3. Signage Appearance and Display
    • 3.4. Sign Mounting and Protection
    • 3.5. Vandal Resistance
  • 4. INCORPORATION OF LANE CONTROL SIGNS (LCS)
  • 5. FUTURE RESEARCH
  • Detailed design of public education programs
  • Detailed design of enforcement programs
  • School zone speed limits and their benefits
  • VSL application for work zones
  • Use of smaller sign size for tunnels
  • Use or overuse of flashing yellow conspicuity devices
  • Future research and measurement of VSL effects
  • Integration with other ITS devices
  • National guideline for VSL
  • 6. SUMMARY OF RECOMMENDATIONS
  • REFERENCES