The Interrelationships between Speed Limits, Geometry, and Driver Behavior

The relationship between speed and safety continues to be a high-priority research topic as numerous states consider speed limit increases. This study leveraged data from the Second Strategic Highway Research Program (SHRP2) Naturalistic Driving Study (NDS) to examine various aspects of driver behavior, including speed limit selection and engagement with in-vehicle distractions, as well as the impacts of these behaviors on crash risk while controlling for the effects of traffic, geometric, and environmental conditions. High-resolution time-series data were analyzed to examine how drivers adapt their speed on roadways with different posted limits, in speed limit transition areas where increases or decreases occur, as well as along horizontal curves, both with and without posted advisory speeds. The research also involved an investigation of the circumstances under which driver distraction is most prevalent. The factors associated with crash and near-crash events were compared with similar data from normal, baseline driving events across various scenarios to improve understanding of the nature of the precipitating events. Driver responses, including reaction times and deceleration rates, were examined during the course of crash and near-crash events to determine how driver response varied across various scenarios. Ultimately, this research provided important insights as to how drivers adapt their behavior and how these behaviors, in turn, influence the likelihood of being crash involved.


  • English


  • Status: Completed
  • Funding: $50000
  • Contract Numbers:


  • Sponsor Organizations:

    Midwest Transportation Center

    Iowa State University
    2711 S Loop Drive, Suite 4700
    Ames, IA  United States  50010-8664

    Office of the Assistant Secretary for Research and Technology

    University Transportation Centers Program
    Department of Transportation
    Washington, DC  United States  20590
  • Performing Organizations:

    Iowa State University, Ames

    Institute for Transportation
    2711 South Loop Drive, Suite 4700
    Ames, Iowa  United States  50010-8664
  • Principal Investigators:

    Savolainen, Peter

  • Start Date: 20160515
  • Expected Completion Date: 20181130
  • Actual Completion Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 01607452
  • Record Type: Research project
  • Source Agency: Midwest Transportation Center
  • Contract Numbers: DTRT13-G-UTC37
  • Files: UTC, RIP
  • Created Date: Aug 4 2016 3:43PM