A big step forward for ADOT's wrong-way detection and warning system

By Doug Nintzel / ADOT Communications

Wrong-way driver system layoutThe use of thermal detection cameras to spot wrong-way vehicles on freeway off-ramps along Phoenix-area freeways will continue to grow, especially after the cameras have worked well as part of a pilot project along Interstate 17

As one example, you can look ahead to significant stretches of Loop 101 currently being widened to also have the thermal camera wrong-way vehicle alert technology added.

ADOT began operating the I-17 alert system in January 2018 along the 15-mile stretch of the Black Canyon Freeway between the I-10 “Stack” interchange near downtown and the Loop 101 interchange in the north Valley.

Thermal cameras were the key components installed to detect wrong way vehicles and immediately alert both ADOT and the Arizona Department of Public Safety so troopers can respond faster than waiting for 911 calls and operators in the ADOT Traffic Operations Center can quickly post warning messages for other drivers with just the push of a button.

ADOT’s I-17 system, a first-in-the-nation effort, was designed to reduce the risks created by often-impaired wrong-way drivers. Our assessment found the thermal cameras are very reliable in detecting those vehicles. 

ADOT’s look at data from the I-17 project shows more than 100 wrong-way drivers set off alerts when thermal cameras detected their vehicles. More than 85 percent of the drivers made a self-correcting turn on an exit ramp without entering the freeway. The I-17 system includes specialized background-illuminated signs along off-ramps that light up toward a potential wrong-way driver in an effort to get that driver’s attention.

While the I-17 system went through testing, ADOT converted thermal cameras already in use for traffic signal timing so they also can detect wrong-way vehicles. Cameras at Loop 101 interchanges between 59th Avenue and Bell Road in the northwest Valley were among those set for such detections.

The majority of interchanges along the new Loop 202 South Mountain Freeway have thermal cameras set up to send wrong-way vehicle alerts to ADOT and AZDPS. Wrong-way vehicle technology projects are underway along Loop 303 from I-10 in the West Valley on up to the I-17 interchange in north Phoenix. 

Thermal cameras also will be in place at off-ramps along the Loop 101 Price Freeway between Baseline Road and Loop 202 in Chandler and the Loop 101 Pima Freeway between I-17 and Princess Drive in the north Valley. The wrong-way vehicle alert technology was added to the ongoing widening projects taking place in those areas.

ADOT will pursue opportunities to deploy thermal cameras along other Valley freeways as well as state highways, starting with rural interstates, as funding and necessary fiber-optic infrastructure become available. ADOT’s assessment of the I-17 pilot system also recommends installing the illuminated, flashing “Wrong Way” signs at urban locations as funding allows.

While we will continue to stress that technology can’t keep a wrong-way driver from getting behind the wheel, nor can it physically prevent a crash, it continues to show that it is an important tool to use to alert law enforcement and warn other freeway drivers when a wrong-way vehicle is detected.