PHOENIX — 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 Director John Halikowski said the study sets the stage for the agency to develop and test a unique and innovative system to detect and track wrong-way drivers, improving opportunities for law enforcement officers to respond.

“While there are tremendous challenges in trying to prevent often-impaired drivers from entering a freeway in the wrong direction, we’re looking at a unique system to detect these vehicles quickly and warn Arizona state troopers, ADOT and other drivers,” Halikowski said.

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.

“We believe this will be a first-of-its kind system featuring the use of our in-pavement traffic sensors to track wrong-way vehicles,” Halikowski said.

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.

“There is no 100 percent solution for wrong-way driving, especially when impaired drivers are involved,” said DPS director Colonel Frank Milstead. “But if technology can be used to quickly notify our state troopers of a wrong-way driver, we can work to reduce the risk of a tragedy.”

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.

On several freeway off-ramps, ADOT in the past year also has begun testing different versions of wrong-way vehicle detection and warning systems manufactured by private companies. Some of that technology is expected to be incorporated into the future prototype system.

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.

“Technology alone cannot prevent all wrong-way tragedies, but ADOT’s study and prototype for detecting and warning us about wrong-way drivers represent a positive next step,” said Alberto Gutier, director of the Arizona Governor’s Office of Highway Safety. “In addition to engineering, enforcement and education, there’s another ‘E’ to consider. It stands for everyone. We all need to work harder to keep friends, family and strangers from driving while impaired.”

From the study

• From 2004 through 2014, there were 245 wrong-way crashes with 91 fatalities in Arizona.
• About 65 percent of wrong-way drivers in Arizona crashes were documented as impaired during the study period, compared to 5.4 percent among all crashes.
• Twenty-five percent of Arizona’s wrong-way crashes were fatal, compared to less than 1 percent of all crashes.
• Fifty-three percent of wrong-way crashes were on urban divided highways and 47 percent occurred on rural divided highways.
• Interstate 17’s 39 miles in the Phoenix metro area had 26 wrong-way crashes during the study period and the most confirmed wrong-way crashes and fatal wrong-way crashes per mile in the state.
• Among rural areas, SR 89A in the Verde Valley had the highest rate of wrong-way crashes per mile, with three wrong-way crashes over 14 miles.
• Interstate 10 near Quartzsite had three fatal wrong-way collisions along a 16-mile stretch during the study period.
• Wrong-way crashes were more common after dark. Wrong-way crashes were more common on weekends.
• The majority of wrong-way drivers in Arizona were ages 16 to 35.
• Sixty-five percent of wrong-way drivers were male, 25 percent were female and 10 percent were documented as gender unknown.
• There was no significant difference between Arizona’s figures and national figures on wrong-way crashes.