Interrelations Between Crash Rates, Signal Yellow Times, and Vehicle Performance Characteristics: Phase II

The Phase II project has conducted extensive field observations of driver responses during a yellow phase at six intersections of high accident frequency with a specially-designed image processing system. The collected field data includes the speed evolution of drivers during the yellow phase, their decisions, traffic flow conditions, vehicle type, gender, signal controls, and geometric features of the target intersection. The analysis results from the sample size of 1123 drivers have confirmed the hypothesis that the dilemma zone at signalized intersections is not static, but dynamic in nature with its range and location varying with driving behaviors, the yellow phase duration, and the surrounding traffic conditions. Intersections having aggressive driving populations cannot effectively eliminate their dilemma zones with an extension of their yellow phase durations. The dilemma zone for aggressive and conservative driving populations are generally distributed at different locations from the intersection stopline. The standard practice of using the average driver data for computing the dilemma zone is likely to reach misleading conclusions.


  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Appendices; Figures; Photos; References; Tables;
  • Pagination: 126p

Subject/Index Terms

Filing Info

  • Accession Number: 01535717
  • Record Type: Publication
  • Report/Paper Numbers: MD-06-SP508B4B
  • Contract Numbers: SP508B4B
  • Created Date: Aug 4 2014 11:08AM