INCLEMENT WEATHER SIGNAL TIMINGS

This study examines traffic signal timing in inclement weather conditions. With the completion of the Utah Department of Transportation's (UDOT) Advanced Traffic Management System (ATMS), UTDOT will have the capability to change signal timing plans from a central location by communicating with each controller through fiber optic technology. With this ability it has become feasible to have a library of special signal timing plans, one of which could be for inclement weather conditions. Traffic data was collected over a range of seven inclement weather severity conditions at 2 intersections. The results of the data collection indicate that the largest decrease in vehicle performance occurred when slush begins to accumulate on the road surface. After this critical point, saturation flows decreased by 20% and speeds decreased by 30%. Start-up lost times also increased by 23%. Based on the collected data and research it was recommended that UDOT develop and implement modified coordinated signal timing plans for the major signalized corridors in the Salt Lake Valley. The plans can easily be developed by modifying the data used to create standard "dry" signal timing plans and by changing a small number of other parameters. In addition, it was recommended that signal timing plans be manually "switched on" by a trained operator or engineer once an alarm identified the potential need. The trigger for the alarm might include observed reductions in travel speeds by mid-block detectors or reduced saturation glows from stop bar detectors. It would be necessary to consider four criteria to maximize the signal timing plan. These are: 1. The storm must be sufficiently severe to cause "inclement" weather conditions. 2. The storm duration must be predicted to continue to cause inclement surface conditions for at least 20 minutes to allow for the negative effects of transitioning from one signal timing plan to another to be minimized. 3. The storm must affect a sufficient length of corridor to benefit the majority. 4. Traffic volumes must be substantial enough to warrant the time to switch a signal timing plan.

• Record URL:
  https://www.ugpti.org/resources/reports/details.php?id=365
• 
• Record URL:
  https://rosap.ntl.bts.gov/view/dot/64662
• Corporate Authors:

  Mountain-Plains Consortium

  North Dakota State University
  Fargo, ND  United States  58108
• Authors:
  • Martin, P T
  • Perrin, J
  • Hansen, B
  • Quintana, I
• Publication Date: 2000-7

Language

• English

Media Info

• Features: Appendices; Figures; References; Tables;
• Pagination: 103 p.

Subject/Index Terms

• TRT Terms: Advanced traffic management systems; Detectors; Fiber optics; Saturation flow; Signalized intersections; Slush; Time duration; Traffic data; Traffic flow; Traffic signal control systems; Traffic signal timing; Traffic speed; Traffic volume; Weather conditions
• Uncontrolled Terms: Inclement weather
• Subject Areas: Highways; Operations and Traffic Management; I73: Traffic Control;

Filing Info

• Accession Number: 00811887
• Record Type: Publication
• Report/Paper Numbers: MPC Report No. 01-120
• Files: UTC, NTL, TRIS
• Created Date: Jun 22 2001 12:00AM