The Arizona Department of Transportation is implementing new thermal cameras to detect wrong-way freeway drivers.

The $3.7 million project is being installed along a 15-mile stretch of I-17 between I-10 to the south and northern segment of Loop 101. ADOT engineer Jim Windsor said the cameras will be placed at on-ramps in the area.

“There’s detection zones, and based on the fact that the car passing the start of the zone and then going out the other side of the zone, the camera can determine what direction the vehicle is headed so we’ll know that it’s going the wrong way,” Windsor said.

Once a driver enters the freeway, an automatic alert will be sent to DPS patrol officers. Construction of the new system is expected to start in the fall and comes in the wake of several fatal wrong-way crashes in recent weeks.