Dilemma zone protection and signal coordination at closely-spaced high-speed intersections : final report, November 2001.

Details

• Creators:
  Pant, Prahlad D. ; Cheng, Yizong
• Corporate Creators:
  University of Cincinnati
• Corporate Contributors:
  Ohio. Dept. of Transportation ; United States. Federal Highway Administration
• Subject/TRT Terms:
  Dilemma Zone Electronic Traffic Controls--Research--Ohio Offsets (Traffic Signal Timing) Traffic Signals Traffic Signal Timing
• Publication/ Report Number:
  FHWA/OH-2001/12
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States
• Edition:
  Final report.
• Corporate Publisher:
  United States. Federal Highway Administration
• Abstract:
  A feasibility study of dilemma zone problems, performed by collecting and analyzing traffic flow data at a high-speed signalized intersection, showed that the maximum green extension or cutback needed to get a vehicle out of the dilemma zone is generally no more than two seconds. Scanning all vehicles on a link just seconds before the beginning of a yellow interval may extend or cut back the green interval so that vehicles can avoid the dilemma zone. For each vehicle approaching an intersection on a link about to turn yellow there is a time interval that (a) the vehicle will be in dilemma zone without green extension (or cutback) or (b) it will be in dilemma zone when there is T seconds of extension (or cutback). The task becomes to find the smallest nonnegative integer T that is not in any of these time intervals and extend or cutback the current interval by T seconds. This T can always be found and assuming there are no other restrictions, dilemma zones can be avoided and the extension or cutback is done at most once for each green interval. The simulation study, performed by modifying the source codes of NETSIM, showed that the signal timing generated by a bandwidth maximization program (PASSER II) resulted in a lower number of vehicles in dilemma zone than that generated by a delay minimization program (TRANSYT-7F). Additionally, the signal timing generated by the combination of the two programs, that is, by minimizing delay within the constraint of bandwidth maximization, resulted in even lower number of vehicles in dilemma zone than those generated by each program alone. The technique developed in this study can be implemented if the speeds and positions of all vehicles in the roadway can be recorded at small time intervals (e.g., 1 sec.). Recommendations are made for implementing and testing the developed technique.
• Format:
  PDF
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:2d889f04bea6992cf5ca848544543a3d306323b7778e8d8f3693ce785c7be24a
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/14967/dot_14967_DS1.pdf
• File Type:
  [PDF - 2.35 MB ]