Surtrac installed equipment at nine intersections around Penn Circle in June 2012, and nine along Penn Avenue near Bakery Square this year. It intends to have 49 in the city in 2015.

The advantage of Surtrac’s technology is that it coordinates flows for many directions of travel. Most adaptive traffic systems on the market are designed to handle straight-line corridor traffic not in urban areas.

Surtrac’s equipment costs about $20,000 per intersection and can be installed in a day, without modification to equipment or roads.

Tests in the Penn Circle area measured performance on 12 routes during four periods of the day, using GPS tracking. Travel time improved, ranging from 32.8 percent at midday to 17.5 percent in the evening. Stops were reduced by 52.6 percent at midday, 29.1 percent during morning rush, and 34.9 percent in the evening commute. Wait times dropped 47.8 percent during mornings and 35.6 percent during evenings.

The system operates independently at each intersection but is on a network that communicates with other units. If one goes down, others nearby still operate.

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