State officials say new thermal cameras to detect wrong-way drivers on Phoenix-area freeways are being tested and already have successfully alerted authorities to two instances of people driving the wrong way.
The Arizona Department of Transportation says there weren't any crashes associated with either incident.
A camera at a Loop 101 interchange detected a driver entering the freeway in the wrong direction early Sunday. Troopers found that vehicle stopped on the freeway's shoulder.
Troopers couldn't locate the other wrong-way driver, who began to enter the Loop 101 on an off-ramp before turning around early Monday.
ADOT is testing the cameras while it installs a pilot wrong-way vehicle detection and warning system along 15 miles of Interstate 17 in Phoenix. The system is scheduled to be fully operational by early 2018.