Line 4 buses now running entire route with Transit Signal Priority
TriMet, with the help of the City of Gresham, recently activated eight additional transit signal priority (TSP) intersections along Division Street in Gresham. This recent TSP activation means that the entire Line 4-Division/Fessenden route will receive signal priority the full length of the route, improving service along the roughly 25-mile line. More than 250 intersections, including Division Street within the city limits, are already equipped with TSP technology.
Developed in the mid-1990s, TSP uses the same equipment that emergency vehicles use to get intersection priority of a traffic signal. When the bus is late, the intersection receives a call and extends the green light for the bus or shortens the red light. As the bus passes the intersection, the call is dropped and the signal light returns to normal operation. The system turns off and on automatically, without the operator doing anything.
One major difference between priority for emergency vehicles and buses is that emergency vehicles receive high priority while buses receive low priority at traffic signals. TSP does not automatically give a bus priority at a traffic signal. This capability to “extend the green” is only enabled when buses are late, which is determined by the on-board computer or transit tracker.
“TriMet, along with our regional partners, are working together to continue to invest in our system, improving transit efficiency and the overall rider experience,” said TriMet General Manager Neil McFarlane. ““For our riders, the trip will be more reliable, which is one of their top priorities.”
One of the main objectives of TSP is to reduce bus travel time. Currently, TSP is being used in many locations throughout the TriMet system. Buses using TSP experience less delay, decreasing travel time, which increases on-time performance, overall efficiency and reliability.
The overall objective of TSP is to create an integrated regional system to increase schedule consistency, which enables improvements in on-time performance and can lead to cost savings with fewer buses needed. TSP has been proven to:
• Improve schedule reliability
• Reduce time inconsistencies
• Improve fuel savings and air quality benefits
• Increase ridership through service dependability
Future plans call for gradual expansion of TSP technology along other frequent service corridors in Gresham.
TriMet, along with the City of Portland and other regional partners, identified corridors to roll out TSP technology in the early 2000s.
As a joint effort, TriMet and the City of Portland created the Streamline program, a package of capital projects and service improvements designed to improve service to all passengers and provide operating efficiencies to TriMet. The program was a result of a $4.5 million federal earmark the City of Portland pursued under the Transportation Equity Act for the 21st Century (TEA-21), and was implemented through an Intergovernmental Agreement (IGA) between the City of Portland and TriMet.
This program required investments both on the part of TriMet and the City of Portland. Key investments on the City’s part were the installation of transit signal priority at 275 intersections and installation of signal priority devices on nearly the entire TriMet bus fleet. TriMet’s key investment was an annual contribution toward the operating cost of the City’s streetcar line. Other changes included installing curb extensions, combining bus stops and removing bus pullouts.
According to the Journal of Public Transportation (2006), TriMet had been estimated to save approximately $13.4 million over eight years. Additionally, through the implementation of the Streamline program (along with other transit improvements such as exclusive bus lanes and stop improvements), TriMet buses improved in efficiency and reduced their fuel usage.