Bus Priority Signalling

Much of the gains in traffic relief we will see in the coming years comes from signal assist, automatic lane guidance. This post is bout signal assist for buses and BRT. It will take a few updates to fill in the references, but the basic price point for adding signal control is about $20,000 at the low end. Thee has been a lot of studies, and I have read the most important ones. Over the ext day or so, I will fill in the key quotes and hopefully reference the important research on the topic.

The following abstract from Chattanooga, TE is typical:

"The Chattanooga Area Regional Transportation Authority (CARTA) installed a new transit signal priority system to improve on-time performance for buses operating in a heavy retail area of Hamilton Place. Instead of increasing their fleet size and adding more buses to compensate for increased traffic delay, the city installed a traffic signal priority system for $250,000. Twenty-seven agency buses were equipped with transit signal priority transmitters, and 10 intersections on Gunbarrel and Shallowford roads and near the mall were equipped with receivers. The transmitter aboard the bus automatically transmits a signal to the receiver. If the traffic control light is about to change to red, the green time is extended 10 to 15 seconds to allow the bus to pass. Overall, the system was expected to improve operational efficiency and have minimal impacts on other traffic."

The parameter to watch is cost per intersection, at $25,000 this implementation is still on the low side.


NYC had a trial on Staten Island to cut transit time. They call it Transist Signal Priority:

"TSP technology was installed aboard 300 New York City Transit buses on Staten Island and at 14 intersections along the critical 2.3-mile Victory Boulevard/Bay Street corridor to and from the ferry terminal in St. George. The system operates in the ferry-terminal bound direction during the morning rush-hour period and outbound during the evening rush period, and is used by 19 bus lines and 49,000 daily passengers."

Their cost per intersection was a little high, but they installed more technology on the 300 buses used in the trial. In a moment I can get into the various choices transit authorities make regarding bus installed technology.

The best overall review of Transit Signal Priority comes from England in this online report. This report discusses the technologies of TSP, as well as other aspects. My position, right now, is that vision based traffic and bus detections will become the norm. I like this technology because vehicle detection by computer visions makes the entire traffic corridor available to all vehicles and to control, uniformly.

Stay tuned.