Bus Transit Signal Priority (TSP) is an important tool that increases bus speeds and reliability, thereby improving transit system efficiency and effectiveness. Transit agencies implement a wide variety of TSP strategies and parameters, and report different levels of benefits from TSP implementations in various traffic conditions and right-of-way treatments (e.g. mixed vs. dedicated guideway). Currently, only fragmented documentation exists on the TSP strategies and parameters in place at different agencies and there has not been a systematic effort to understand the link between TSP strategies and parameters, and the level of benefit realized. As agencies may have limited understanding of what strategies and parameters are in use in other jurisdictions, and how these decisions tie to the benefits of TSP, it is difficult to weigh the benefits against the tradeoffs involved.
This synthesis study aims to document the current practice of transit systems use of TSP to meet the different objectives under diverse conditions; it will provide an overview of 1) TSP strategies and parameters, 2) the resulting benefits and 3) an assessment of to what extent the disparity in benefits realized are driven by strategy and parameter choices. Information to be gathered include (not an exhaustive list):
· Planning and Objectives
o Goals and criteria for TSP deployment (reasons behind the decision).
o Feasibility studies for TSP deployment (simulation and field studies)
· TSP deployment characteristics
o Number of intersections
o Number of vehicles
o Type of TSP ( conditional vs. unconditional)
o Conditions for requesting priority (time of day, schedule/headway adherence, load factor or occupancy, etc.)
o Type of priority given (early green, green extension, phase skipping, etc.)
o Set values for the above strategies and their limitations ( e.g. Blackout recovery period)
· Other design factors and operating context (right-of-way treatment, signal timing optimization, stop location, intersection spacing, level of service, stakeholders, congestion, and signal system design, etc.)
· Benefits (e.g. signal delay reduction, travel time saving, on-time performance/reliability)
· Supporting Technology – Communications system, Integration protocols, Signal system, Automatic Vehicle Location and Automated Passenger Counter and other systems
· Maintenance and Operations – frequency of revisiting strategies and parameters, performance monitoring
The principal investigator will conduct a literature review focusing on modern deployments (both domestic and international) and a survey of selected North-American transit systems that utilize TSP. The report should also include five case examples that will gather information on the state-of-the-practice, emphasizing lessons learned, current practices, and challenges. The final report will document gaps in knowledge and research needs.
Alan Danaher and Herbert S. Levinson, TCRP Report 118: Bus Rapid Transit Practitioner’s Guide, Transportation Research Board of the National Academies, Washington D.C., Washington, D.C., 2007.
Bailey Lozner, “Large-Scale Transit Signal Priority Implementation: District of Columbia’s Path to Success,” Transportation Research Board Paper 18-04233 (2018).
Diane Quigley, Transit Signal Priority Implementation Guidance, July 7, 2014.
Paul Ryus, Kelly Laustsen, Kelly Blume, Scott Beaird, and Susan Langdon, TCRP Report 183: A Guidebook on Transit-Supportive Roadway Strategies, The National Academies Press, Washington, D.C., 2016.
First Panel: October 2, 2018, Washington, DC
Teleconference with Consultant: 10/26/2018
Second Panel: June 4, 2019, Washington, DC
James Bunch, Sabra-Wang & Assoicates
Fabian Cevallos, Florida International University
Kristin Demasi, Metrolinx- Province of Ontario Canada
Mark Irvine, Washington Metropolitan Area Transit Authority
Owen Kehoe, King County (WA) Metro Transit
Robert Lim, San Francisco Municipal Transportation Agency
Taqhi Uddin Mohammed, Pace Suburban Bus Service
Gary Nyberg, Metro Transit
Dan Turk, Office of Planning & Environment- Capital Project Development