City expands use of high-tech traffic signals

Officials, CMU students team up again to reduce red-light wait times

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The city and Carnegie Mellon University are expanding a network of high-tech traffic signals that monitor flow and instantly react, changing their timing to move vehicles through intersections more efficiently.

The expansion, to be done by early next year, will add the signals to several intersections along Baum Boulevard and Centre Avenue, stretching from East Liberty to Oakland.

When the work is done, the system will extend from Penn and Braddock avenues in Point Breeze through Larimer, East Liberty, Friendship, Bloomfield, Shadyside and Oakland, with 49 intersections equipped with the smarter signals.

The signals use cameras or radar to monitor traffic and are able to communicate with one another to minimize wait time for drivers. Deployment of 18 such signals in East Liberty is credited with reducing wait times by 42 percent and travel time by 24 percent, officials said.

"Imagine if traffic signals had the ability to see the traffic that was there. Then imagine the traffic signals had the ability to talk to each other, second by second," Mayor Bill Peduto said at a news conference. "It's not something from George Jetson. It's something that's happening right here in Pittsburgh today."

The pilot project that upgraded the East Liberty signals "produced some really surprising results," said Allen Biehler, executive director of the University Transportation Center at CMU. "You've got to kind of pinch yourself and say, 'Is this for real?' "

UPMC, the Hillman Foundation, the Heinz Endowments and R.K. Mellon Foundation are paying about $1.3 million of the $1.8 million project cost, with federal, state and city money covering the rest.

Stephen Smith, a robotics research professor and director of CMU's Intelligent Coordination and Logistics Laboratory, said the technology does not use pavement sensors like those in place at many suburban intersections. Instead, cameras or radar equipment are mounted and connected to a computer placed in the control box at each intersection.

The computer formulates a plan based on traffic observations and communicates it to neighboring intersections. It can instantly adjust to accommodate surges caused by disabled vehicles, crashes, street closures or bursts of traffic after events.

CMU will work next on ways to improve pedestrian and public transit flow. Mr. Peduto said he expects further expansion of the signal network as well.

"We're in a part of the city that's growing very quickly," he said at the conference, held at Morrow Park in Bloomfield.

"We don't have the capacity to tear down houses and make wider roads" to speed traffic, Mr. Peduto said.

"We do have the ability to think about it and do it smarter."

Jon Schmitz: or 412-263-1868. Visit the PG's transportation blog, The Roundabout, at Twitter: @pgtraffic.

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