Comprehensive Evaluation of Transit Signal Priority System Impacts Using Field Observed Traffic Data

To improve the level of service for Community Transit (CT) buses, the South Snohomish Regional Transit Signal Priority (SS-RTSP) project was launched. To understand the overall benefit of this project, the SS-RTSP system was tested and evaluated after the hardware and software had been installed on the 164th Street SW corridor (Phase One) and the SR 99 corridor (Phase Two) in Snohomish County, Washington State. In this study, impacts of the SS-RTSP system on both transit and local traffic operations were quantitatively evaluated on the basis of field-observed data. Simulation models were also built and calibrated to compute measures of effectiveness that could not be obtained from field-observed data. With simulation models and field observed data, the impacts of the SS-RTSP system on both transit and local traffic operations were quantitatively evaluated. The evaluation results showed that the SS-RTSP system provided remarkable benefits to transit vehicles, with insignificant negative impacts to local traffic on cross-streets under the current coordinated control strategy. The overall impact of the SS-RTSP system on local traffic at each entire intersection was not statistically significant at the p=0.05 level. To improve the performance of the current SS-RTSP system, more transit vehicles can be made TSP eligible. The average number of granted TSP trips was only 16.96 per day per intersection during the Phase One test and 14.40 during Phase Two test. Given that negative impacts of the SS-RTSP project on local traffic were not significant, more transit trips can be granted with proper TSP treatment to generate more benefits from the SS-RTSP system. Further simulation-based investigations on TSP system operations and optimization were conducted. The research findings indicated that to achieve the best operation efficiency, the compatibility between TSP control schemes and signal control coordination should be strengthened to minimize transit disruption to signal coordination. TSP systems must be fully tested under different coordinated control plans prior to implementation.

• Record URL:
  • http://www.wsdot.wa.gov/research/reports/fullreports/699.1.pdf
• 
• Supplemental Notes:
  • This report is a revised edition of Report No. TNW2007-06, which has the same title.
• Corporate Authors:

  University of Washington, Seattle

  Transportation Northwest Regional Center X (TransNow)
  Box 352700, More Hall
  Seattle, WA  United States  98195-2700

  Washington State Department of Transportation

  Transportation Building, 310 Maple Park Avenue SE, P.O. Box 47300
  Olympia, WA  United States  98504-7300

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Wang, Yinhai
  • 0000-0002-4180-5628
  • Hallenbeck, Mark E
  • Zheng, Jianyang
  • Zhang, Guohui
  • Corey, Jonathan
  • Ma, Xiaolei
• Publication Date: 2008-6

Language

• English

Media Info

• Media Type: Print
• Edition: Final Technical Report
• Features: Figures; References; Tables;
• Pagination: 96p

Subject/Index Terms

• TRT Terms: Bus priority; Bus transit operations; Field studies; Highway operations; Impact studies; Level of service; Measures of effectiveness; Signalized intersections; Simulation; Traffic delays; Traffic signal control systems; Transit buses
• Geographic Terms: Snohomish County (Washington)
• Subject Areas: Highways; Operations and Traffic Management; Public Transportation; I73: Traffic Control;

Filing Info

• Accession Number: 01104814
• Record Type: Publication
• Report/Paper Numbers: WA-RD 699.1
• Contract Numbers: Agreement T2695, Task 60
• Files: TRIS, ATRI, USDOT, STATEDOT
• Created Date: Jul 17 2008 2:35PM