Smart traffic system to reduce first responder deaths

other responders and will know their exact locations, Head explained.

By contrast, the systems installed at most intersections today fall far short of this. The signals communicate with emergency vehicles by infrared light and the first vehicle in the area pre-empts the signal. Flashing white lights above the signals show that a pre-empt signal has been received, but that just means there’s an emergency vehicle in the area.

If two or more responders are approaching an intersection, they’re not aware of one another or if the signal is being pre-empted for them or someone else, Head noted. This can lead to serious collisions.

In addition to smart control at intersections, the system will allow emergency vehicles at the scene to broadcast their locations so other vehicles not involved in the incident will know which lanes are closed and can select alternate routes to reach other emergencies or to find a clear corridor to hospitals. If additional emergency vehicles are heading for the incident, they will be able to find the fastest routes through traffic.

The vehicles also will communicate with the Arizona 511 network to alert motorists to the traffic problems, allowing them to select alternate routes. This will help cut down on congestion and prevent secondary accidents that often occur when distracted motorists are faced with traffic disruptions.

“Our tests of this system will significantly advance the technology and make intersections safer for emergency responders,” Saleem said. “We also hope it will improve response times where seconds can mean the difference between life and death.”

Local school buses will participate and be equipped with short-range radios to test the system for transit priority.

“If you have a bus that’s behind schedule, you can have the traffic light hold the green longer or give an early green,” Head explained. “If they’re running on time, they can go with the normal stream of traffic.”

Tying transit vehicles to the system could make public transit more attractive because the vehicles would run on time more often.

The UA researchers and Maricopa County also plan to adapt the system to freeway entrance ramps that are controlled by traffic signals.

“If we have a two-lane ramp, you can hold one lane red and turn one green to let everyone go, clearing the way for the emergency vehicle,” Head said. “On one-lane ramps, you can just turn the light green and flush out the cars to clear the way.”

The big question with ramp control – and, in fact, in all this work – is driver behavior, Head noted. “There is a big human factors problem to be solved to get intelligent vehicles properly integrated with drivers,” he said.

The UA researchers have had an ongoing program since the early 1990s of analyzing traffic video to determine how drivers respond to various situations. They will continue to look at driver behavior when testing the system on freeway entrance ramps. Currently, they’re considering tests of the system on the eastbound side of I-10 at Warner Road in Tempe.

Head, who has been working on intelligent traffic design since 1992, says the systems are getting a lot smarter. He is excited about the tests in Maricopa County, which are to run until Sept. 1. The equipment is being installed, and software will be set up in April and May, with tests beginning toward the end of the summer.

The partnership between Maricopa County’s Department of Transportation and UA’s Systems and Industrial Engineering Department has been vital in bringing the intelligent traffic control system to life.

“Our universities have so much talent and can give a lot of benefit to public agencies by doing this kind of applied research,” Saleem said.

“This partnership has been really good for us,” Head added. “Without a real agency to bring this technology into the real world, we would just be off doing research we think is interesting, but the benefits might never reach the public.”