When someone calls 911 about a wrong-way driver, or a detection system flags one, a response begins that most people never see. It moves fast, because the window to prevent a crash is measured in minutes or less.
Understanding how that response works helps explain why the details in your call matter, and why the technology on some Arizona freeways makes a difference.
Two ways a report begins
A 911 call. For most of the road network, the first sign of a wrong-way driver is a call from another motorist who saw headlights coming the wrong way. Dispatchers treat these reports as urgent.
Automatic detection. On some corridors, the road reports it first. ADOT's thermal-camera system on I-17 in Phoenix, which began operating in 2018 with 90 cameras between the I-10 "Stack" interchange and Loop 101, detects vehicles moving the wrong direction. ADOT has extended the technology to the Loop 202 South Mountain Freeway and Loop 303.
ADOT has found that immediate alerts from thermal-camera detection result in faster response times by law enforcement compared with waiting for 911 calls. When the system detects a wrong-way vehicle, the Arizona Department of Public Safety and ADOT are alerted at once.
Several things happen at the same time
A wrong-way response is not a single action. Multiple layers start in parallel.
The wrong-way driver is warned. On detection corridors, internally illuminated "Wrong Way" signs with flashing red lights activate, aimed at the driver who entered. ADOT reports that most detected drivers turned around on exit ramps or pulled into driveways, so this step alone often ends the incident.
Other drivers are warned. ADOT posts alerts on overhead message boards so people approaching the area know to be cautious. ADOT's guidance when you see one of those warnings is to safely move toward the nearest exit as soon as possible.
Law enforcement moves to intercept. DPS troopers, who patrol Arizona's state highways, head toward the reported location. Their goal is to get ahead of the vehicle, warn traffic, and stop the wrong-way driver before a collision.
When troopers have to stop a vehicle
Sometimes warnings are not enough and the vehicle keeps going. In those cases, troopers have to make hard decisions quickly.
In one example described by DPS, in May 2023, two troopers who saw a wrong-way driver on State Route 51 in Phoenix reported it to dispatch, looped back to get ahead of the vehicle, and intentionally collided with it to bring it to a stop. DPS said the driver was confused and that impairment was not a factor. The injuries involved were not life-threatening.
That is an extreme measure, and it reflects what is at stake. Officers place their own vehicles between a wrong-way driver and the public because a head-on crash at highway speed is far worse.
What makes a 911 call useful
Detection covers specific corridors. Across most of Arizona's roads, a call from a driver may be the only report dispatch gets, and good information shortens the time to respond.
When you are safely out of the way, call 911 and try to share:
- The road and which way you were traveling.
- Which direction the wrong-way vehicle is heading.
- The nearest exit, cross street, or milepost.
- A short vehicle description, such as color and type.
- Whether it was still moving when you lost sight of it.
Do not chase or follow the vehicle to get more details. Your safety comes first, and the information you already have is enough.
Do not assume someone else has called. Multiple reports help dispatchers confirm the location and direction of travel.
Supporting the people who respond
First responders handle wrong-way calls knowing the risk to themselves. Things that help them include better detection that buys more time, clear reports from the public, and fewer impaired drivers on the road in the first place. ADOT reports that two out of three wrong-way crashes are caused by impaired drivers.
Every layer that catches a wrong-way driver earlier, whether a lowered sign, a red reflector, a thermal camera, or a fast 911 call, reduces the chance that an officer has to put their vehicle in the way.
How you can help
NMWWD is a Phoenix nonprofit working to make wrong-way crashes rarer through awareness, technology, and community partnership. We are rebuilding our own alert technology with reliability as a core requirement, and it is not available yet.
If you want to support that work and the people on the front line of these calls, get involved or donate.
Sources: Arizona Department of Transportation — I-17 thermal-camera system · Arizona Department of Transportation — Wrong-Way Drivers · Arizona Department of Public Safety — news release on SR 51 wrong-way stop