After completing a comprehensive study of wrong-way driving crashes on state highways and how technology may help reduce the threat, the Arizona Department of Transportation is planning a prototype project to use existing highway sensors to detect wrong-way vehicles and to alert authorities and other motorists.
ADOT's study, which started in January, helped ADOT identify Interstate 17 in the Phoenix area as the best place to establish a prototype system. Initially planning to use a 3- to 4-mile stretch of the interstate, the agency will determine an exact location for the test system as it is developed in the coming year.
The prototype system, as currently envisioned, would enhance in-pavement freeway sensors that now detect traffic traveling in the right direction to also track vehicles going the wrong way. Such detections would alert ADOT's Traffic Operations Center and the Department of Public Safety to the location of a wrong-way vehicle.
The system also would include separate wrong-way vehicle detectors on freeway on-ramps within the test area, as well as technology to quickly post warnings on overhead message boards for drivers going the right way. Existing freeway on-ramp traffic signals, known as ramp meters, also would display a solid red light to hold traffic from entering the freeway when a wrong-way vehicle is detected.
A key goal of a prototype system is significantly improving alerts for law enforcement, including the Arizona Department of Public Safety, compared to relying on information relayed by 911 callers.
ADOT has taken extensive steps already to address the threat of wrong-way driving, including installing hundreds of larger and lowered Wrong Way and Do Not Enter signs on more than 100 on-ramps along Phoenix-area freeways and rural state highways. Countermeasures also have included large white "right way" arrows on dozens of off-ramps. The arrows are outlined with red reflectors that glow red toward wrong-way drivers.
ADOT's study also pointed to a societal problem that no technology can address: the role of impaired driving in wrong-way crashes. Two out of three wrong-way crashes on Arizona highways from 2004 to 2014 involved impaired drivers.