Speed Modification Factors for Speed Management within the Safe System Approach

The Safe System Approach (SSA) is a comprehensive strategy to prevent fatal and serious-injury crashes that works by building and reinforcing multiple layers of protection. Success in implementing the SSA requires an understanding of safe system speed applications in planning, design, and operational contexts. However, there is limited understanding of how speed management countermeasures influence operating speeds and resulting injury severity. Furthermore, there is limited research on speed changes related to the evolving concept of achieving injury-minimization target speeds for various roadway types and land use contexts. Research is needed to fill these knowledge gaps. OBJECTIVE: The objective of this research is to develop a guide that provides: An injury-minimization speed management approach for achieving safe system speeds by applying speed modification factors (SMFs); A framework for developing and applying SMFs, including a pilot series of SMFs; Strategies for communicating speed management changes to the public and to public officials.

• Record URL:
  • http://apps.trb.org/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=5876
• Supplemental Notes:
  • Contract to a Performing Organization has not yet been awarded.

Language

• English

Project

• Funding: $725,000.00
• Contract Numbers:

  Project 17-143

• Sponsor Organizations:

  National Cooperative Highway Research Program

  Transportation Research Board
  500 Fifth Street, NW
  Washington, DC  United States  20001

  American Association of State Highway and Transportation Officials (AASHTO)

  444 North Capitol Street, NW
  Washington, DC  United States  20001

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Project Managers:

  Li, Zhiye

• Start Date: 20260808
• Expected Completion Date: 0
• Actual Completion Date: 0

Subject/Index Terms

• TRT Terms: Injury severity; Speed control; Speed limits; Traffic speed
• Identifier Terms: Safe System Approach
• Subject Areas: Highways; Operations and Traffic Management; Safety and Human Factors;

Filing Info

• Accession Number: 01956837
• Record Type: Research project
• Source Agency: Transportation Research Board
• Contract Numbers: Project 17-143
• Files: TRB, RIP
• Created Date: May 29 2025 1:17PM