Getting there: City Line bus route will use new system to shorten waits at red lights

As emergency vehicles quickly weave their way through heavy traffic to get to their destinations, street lights in some cities change from red to green just as the vehicles arrive, allowing for seamless travel.

In 2023, some of Spokane’s buses will start using the same technology to get passengers to their destination on time, even in heavy traffic.

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

Buses will be able to communicate their current location, speed and whether they’re running on time to upcoming traffic signals. A bus running late will in some circumstances prompt the signal to more quickly switch from red to green or stay green longer.

The system is not suitable for all areas of the city, however.

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

But the Transit Signal Priority system will be able to leverage Spokane’s more technologically advanced signals that in some areas are capable of changing their cycle depending on the circumstances, such as during rush hour, wrote Carly Cortright, chief communication and customer service officer for the transit authority.

It’s difficult to predict how much the system will cut down on a given ride’s travel time, but it will primarily be used during peak travel hours to keep routes on schedule.

“Signal priority on the City Line will initially emphasize maintaining service reliability, helping to ensure buses maintain schedule,” Cortright wrote. “The application of signal priority, therefore, will vary by time of day.”

Minimizing delays is particularly important for the City Line, which will have buses arriving at stops every 7.5 minutes during peak hours.

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

The signal priority system is just one of many design choices meant to keep the city’s rapid transit routes on schedule with minimal delays, such as pre-boarding ticketing, all-door boarding and transit priority lanes.

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