Signal Timing Under Saturated Conditions

This report provides guidance to practitioners for strategies and tactics that will help mitigate the effects of congestion at traffic signals. The focus was on methods that made use of settings within the local intersection controller rather than on network-level strategies. The strategies are defined in terms of objectives, with the objectives shifting from traditional performance measures to maximizing throughput and managing queues. A range of experts were consulted on their strategies and tactics for signal timing at congested intersections, and a comprehensive discussion of these methods is presented. Some strategies were studied further, particularly the commonly held belief that longer cycles are more efficient, and the effect of buses on signal timing in grid networks. The research found that long cycles are not more efficient, and at intersections where long queues starve turn lanes (and consequencly departing turners dilute the traffic stream served at the stop line), the shortest cycle that emptied the queue back to the upstream end of the turn lanes was found to provide the greatest throughput. In grid networks, the cycles that is just long enough to reliably serve on bus from a near-side stop was found through simulation to provides the least development of residual queue. Methods of presenting congestion for these cases in terms of throughput and residual queuing were developed to correspond to the objectives of maximizing throughput and managing queues.

• Record URL:
  http://ops.fhwa.dot.gov/publications/fhwahop09008/fhwahop09008.pdf
• Record URL:
  http://ops.fhwa.dot.gov/publications/fhwahop09008/index.htm
• 
• Record URL:
  https://rosap.ntl.bts.gov/view/dot/16627
• Corporate Authors:

  Booz-Allen and Hamilton, Incorporated

  8201 Greensboro Drive, Suite 609
  McLean, VA  United States  22102

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Denney, R W
  • Head, L
  • Spencer, K
• Publication Date: 2008-11

Language

• English

Media Info

• Media Type: Print
• Pagination: 80p

Subject/Index Terms

• TRT Terms: Cartographic grids; Strategic planning; Traffic congestion; Traffic control devices; Traffic signal timing; Traffic signals
• Uncontrolled Terms: Online operational tactics; Throughput (Traffic)
• Subject Areas: Highways; Operations and Traffic Management; I73: Traffic Control;

Filing Info

• Accession Number: 01135299
• Record Type: Publication
• Contract Numbers: DTFH61-06-D-00006
• Files: NTL, TRIS, USDOT
• Created Date: Jul 21 2009 8:11AM