GRTC Pulse Richmond BRT by BeyondDC licensed under Creative Commons.

The Pulse bus rapid transit line is the face of modern transit in Richmond. Planners praise it, and riders flock to it. One problem with it, however, is its transit signal prioritization (TSP) system, which some say isn’t delivering on promises to speed buses through red lights.

The perception among the public in Richmond has been that whenever a Pulse bus falls behind schedule, traffic lights should adjust to help bring the bus back on schedule. Pulse passengers whose buses wait out multiple light cycles and feel they have never witnessed TSP shift the lights in transit’s favor aren’t convinced the necessary technology is operating properly or even installed.

Computer simulations for the Pulse in 2015 projected end-to-end trips taking 28-31 minutes. Today riders report that same stretch consumes 37 minutes. So how is TSP supposed to function, and why haven’t riders noticed its effect in Richmond?

What is TSP and how does it work

Here's how TSP works. Image by BaltimoreLINK.

TSP advantages transit in three small but critical ways.

First, TSP can engage “green extension” to hold green lights longer if there is enough give in the cycle to allow it. Second, TSP can trigger an “early green” when a signal cuts a red light short in favor of a bus (usually by stealing seconds from left turns and green lights for minor side streets). Lastly, TSP’s clearest benefit is the “queue jump.” This technique holds back cars to allow buses to seamlessly merge in and out of bus only lanes without other vehicle traffic in their way.

According to Lyne Lancaster, the City of Richmond’s Deputy Director of Parking & Mobility, the Pulse’s TSP system was initially planned to adjust traffic signals in its favor only when its headways were in danger of not being met. In the course of the last year of operations, however, the city began allowing TSP to operate regardless of whether the Pulse is running behind schedule or not. Today, TSP’s goal is to reduce the average delay by 10% on all trips within a day.

A screenshot from the city's TSP monitoring software. Image by City of Richmond.

What TSP is not

While TSP offers some flexibility in light cycles to prioritize transit, Lancaster wants riders to understand that the system “does not make all the lights green no matter what.” That ability to fully override the traffic signals’ normal patterns is known as Traffic Signal Preemption, or more commonly as Emergency Vehicle Preemption (EVP).

According to Carrie Rose Pace, GRTC’s Director of Communications, such a system wouldn’t even be desirable. “Always giving the bus the green light can be as bad or worse to the system performance than never giving it at all,” she said in response to a request for comment.

All 56 intersections along the Pulse’s 7.6-mile-long corridor feature TSP, but the programming of the lights from 25th Street to Lombardy Street (throughout downtown) prioritizes people who walk over transit.

The nuance and complexity of TSP can make its positive effects hard for riders to perceive. Lancaster wants to assure Richmonders that “the current system has been active since opening day and therefore users have always received the benefits of TSP.”

Julie Timm, GRTC’s new CEO, hopes riders will appreciate the valuable impact of TSP even if its effects aren’t always easy to discern.

“TSP has been working and working well. It is important for people to understand that all mobility needs in the corridor need to be managed together to be safe and effective,” Timm said. “The current system design does that well, and sometimes that means that a bus needs to stop at a red light too.”

Wyatt Gordon is the senior policy manager for land use and transportation at the Virginia Conservation Network, and an adjunct professor at Virginia Commonwealth University's Department of Urban Planning. He's a born-and-raised Richmonder with a master's in Urban Planning from the University of Hawai‘i at Mānoa and a bachelor's in International Political Economy from American University.