Getting there: The City Line bus line uses a new system to shorten waiting times at red lights

As emergency vehicles quickly weave through heavy traffic to get to their destination, in some cities the streetlights will change from red to green as vehicles arrive, allowing for a smooth ride.

Beginning in 2023, some of Spokane’s buses will use the same technology to get passengers to their destinations on time, even during heavy traffic.

The Spokane Transit Authority’s new City Line bus route, the 6-mile route between Browne’s Addition and Spokane Community College, which is expected to start next summer, will be the first to use the Transit Signal Priority system. The agency is also considering implementation along the Division and Sprague routes.

Buses will be able to broadcast their current location, speed and punctuality at upcoming traffic lights. A late bus may cause the signal to go from red to green faster or stay green longer.

However, the system is not suitable for all parts of the city.

Much of the city’s downtown core uses traffic signals in a coordinated, timed system, and changing the timing of a signal for a delayed bus could disrupt the entire system, Chief Planning and Development Officer Karl Otterstrom said at a recent meeting of the Spokane Transit Authority’s board of directors .

However, the Transit Signal Priority system will be able to take advantage of Spokane’s more technologically advanced signals, which in some areas may change cycles depending on circumstances, such as during rush hour, wrote Chief Communications and Customer Service Officer Carly Cortright for the transit authority.

It’s hard to predict how much the system will reduce the travel time of a given trip, but it’s mainly used during peak travel times to keep routes on schedule.

“First, signal priority on the City Line will emphasize maintaining service reliability and helping buses stay on schedule,” Cortright wrote. “The application of signal priority will therefore vary depending on the time of day.”

Minimizing delays is particularly important for the City Line, where buses arrive at stops every 7.5 minutes during peak hours.

Similar signal priority systems are already in place at Everett; Provo, UT; and throughout King County, Cortright said.

The signal priority system is just one of many design decisions intended to keep the city’s rapid transit routes on schedule with minimal delays, such as:

Corresponding hardware and software for the City Line will cost $20,000, Cortright said, with an additional undetermined cost of developing priority parameters — the metrics of when signals for an oncoming bus would change.