The East Liberty intersection that prompted a recent rally for pedestrian safety — at the Target store at Penn Circle and Penn Avenue — is one of 18 that Carnegie Mellon University researchers have been monitoring using a traffic control system they developed.

Making use of city cameras already in place, CMU’s Traffic 21 project piloted its Scalable Urban Traffic Control system — Surtrac — at nine East Liberty intersections last year. The city installed the system at nine other intersections, from Penn to Fifth Avenue, last month.

Officials say the system has reduced vehicular emissions by 21 percent and travel times by 25 percent overall. The midday wait time for a green light was almost cut in half. The catch, and potential hazard, is that green arrows for cars light up at the same time the walking figure lights up for pedestrians.

CMU researchers are working on perfecting a pedestrian detection model and have a test mechanism already installed on Penn Circle at Collins Street and at Eastside.

Post-Gazette: Carnegie Mellon University’s East End traffic effort turns to pedestrian safety