Traffic signals getting smarter in Cranberry

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If he thought about it once, he thought it a hundred times or more: If traffic signals can be made technologically smart, why can’t they be made smart enough to respond to real-time circumstances, so that a motorist isn’‍t stuck at a red light when there’s no traffic and gets the benefit of a green signal instead?

It’s a question Cranberry assistant township manager Duane McKee pondered himself. It has also been posed to him by the traveling public more than a few times.

The question has been answered. As traffic signals have gotten smart enough to adjust themselves on a minute-to-minute basis, reflecting the real-time traffic circumstances, Cranberry has purchased the software to install those smarter signals in its most congested corridor that feeds into an intersection —- Route 19 and Freedom Road/Route 228 — crossed by 100,000 vehicles per day.

“It’s the biggest, best and latest thing and we’ve got it,” Mr. McKee said.

By early next year, six signals on Freedom Road between Route 19 and Thorn Hill Extension will be equipped with the necessary software, allowing them to “sense” traffic movement up to 250 feet away and respond accordingly.

Known as “adaptive software signals,” they’re the products of engineering think tanks. “I can’t tell you how many times I’ve answered the phone and there’s a person who wants to know why he or she has to sit at a red light when there’s no traffic [in the opposing lanes.] It seems so simple that there should be a way to move the system around. I’ve thought the same thing myself. Now, we’ve reached the point where there is a system smart enough to do that,” Mr. McKee said.

It has been an incremental progress to this point. Cranberry has been using “smart signals” of one sort or another for more than a decade: The first set uses fiber-optic cables beneath Route 19 to gauge the amount of traffic at a signal; and the second employs cameras to detect traffic volume. Software has been used in conjunction with this evolving information feed to devise traffic signals‘‍ timing plans based on real-life circumstances. Those plans have gotten better and better. But, there have been both hardware and software limitations.

Most of those limitations will be eliminated with the latest generation of signals planned for Freedom Road.

Using radar technology, cameras and sensors attached to signal poles, the half-dozen “smartest” signals will feed data to each other as a network for last-minute adjustments to traffic conditions. The signals will be at Thorn Hill Extension, Haldeman Drive, Commonwealth Drive, Executive Drive, Short Street and Route 19. “The detections are so accurate and reliable that they allow the signals to reach each [signal] phase, keep track of what’s going on behind and in front of them, and move around the timing based on a set of parameters we supply the system. The signals can bounce around to accommodate existing traffic,” Mr. McKee said.

The project costs $50,000 — much lower than have cost if the affected signals were not new enough to be compatible with the adaptive control software. Funding came from a state grant.

The adaptive system will tie into the township’s existing Traffic Operation Center, which uses fiber-optic technology to manage signals’‍ timing plan based (to a certain extent) on the time of the day, traffic predictions and sensor data communicated from the fiber optics to the center.

The new software’‍s algorithms just take that system to a new level of maneuverability.

Before they can begin the new software’‍s installation, Cranberry will be working in the coming months to come up with a solid base plan for traffic expectations. Many significant changes to the traffic corridor are pending.

Among the changes:

• The intersection of Freedom Road and Route 19 is being expanded to allow both east and west left-turn lanes to move concurrently. Now, those left-turn movements are staged. This project, about $2.2 million, began in June and will be done in early September.

• The ramps to Interstate 79 southbound that will eliminate left-turn movements from westbound Route 228 to southbound Interstate 79 will be finished in September or October. Also, the first triple left turns in the region from the driveway to Cranberry Business Park on the south side of Route 228 will be opened when the new interstate ramps open. Together, the project costs about $7 million.

• Traffic signal and intersection improvements at Route 228 and Franklin Road, a $4 million project required as part of the Cardinal Wuerl North Catholic High School construction project, are being made.

When those improvements are complete, the township will implement its period “sync-up project.” Every two years or so, the township looks at each of its three main traffic corridors (Route 19 at Rochester Road, Route 19, and Route 228/Freedom Road) and synchronizes the traffic signals with data that has been collected. The cost is about $200,000 and it yields the information necessary for the township to establish base-line parameters for the new adaptive system.

“This is a huge year for us in terms of traffic management. One of the biggest ever,” Mr. McKee said.

Karen Kane: kkane@post-gazette.com or 724-772-9180.


Karen Kane: kkane@post-gazette.com or at 724-772-9180.

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