Transit signal priority reduced average bus travel times by 7.5 and 15 percent along major bus corridors in Los Angeles and Chicago, respectively.
Results from TCRP Synthesis Report 83.
Made Public Date


Los Angeles, California,
United States


United States


Chicago, Illinois,
United States


Portland, Oregon,
United States

TCRP Synthesis 83: Bus and Rail Transit Preferential Treatments in Mixed Traffic

Summary Information

Transit preferential treatments have been deployed across the United States and around the world in order to improve travel times and reliability of bus and light rail routes. Examples of transit preferential treatments include exclusive lanes and median transitways, transit signal priority, queue jumps and bypass lanes, curb extensions, and stop consolidation. The measured benefits of transit signal priority are reported below. These results are from a synthesis report on Bus and Rail Preferential Treatments in Mixed Traffic, conducted as part of the Transit Cooperative Research Program, and as such, the results are compiled from multiple deployment locations.

Transit signal priority (TSP) for both light rail and transit buses utilizes a detection system to analyze based on the vehicle's distance from the intersection and the speed of traffic, and the signal's phasing, whether the signal will extend its green phase in order to allow the passage of the transit vehicle or if it will shorten the red phase in order to reduce the delay experienced by the transit vehicle. In many systems, buses are not automatically granted priority, but it is instead utilized by vehicles that are running behind schedule to either get back on schedule or, at least, not fall further behind.


Travel Time Savings
  • Travel time savings associated with TSP in North America have ranged from 2 to 18 percent, with typical reductions of 8 to 12 percent.
  • In Los Angeles, the MTA saw a 7.5 percent reduction in travel times along its two BRT corridors (0.3 and 0.5 minute/mile average reductions) after TSP was installed.
  • In Chicago, buses along a TSP corridor along Cermark Road saw an average of 15 percent reductions in travel time.
Bus Delay at Signals
  • In Los Angeles, MTA's bus rapid transit (BRT) routes saw bus delay at intersections with TSP reduced by around 35 percent.
  • In Oakland, along San Pablo Avenue, buses saved an average of 5 seconds per intersection.
  • Overall, studies have shown that reduction in bus delay at TSP enabled signals ranges from 15 to 80 percent.
Cost Savings

TriMet (Portland, Oregon) has Optical Infrared bus detection systems installed at over 275 intersections in the Portland area. Although the "Streamlining" system hasn't allowed for the permanent reduction of the number of peak buses on a route, it has allowed the agency to delay purchasing additional buses by an estimated eight years, while still being able to serve additional passengers.
  • This delay provides approximately $13.4 million in long term savings (12 buses per year for eight years at $140,000 per bus per year) for TriMet.
  • Los Angeles MTA saves approximately $3.3 million per year on its two BRT corridors, due to a traffic signal delay reduction of 4.5 minutes per hour. These cost savings assume a daily savings of $110.25 per bus per day, for 100 buses operating 300 days a year.
Goal Areas
Deployment Locations