Lights to warn of wrong-way Valley drivers
Phoenix area drivers are familiar with freeway entrance-ramp meters that show alternating green and red traffic lights during weekday rush hours.
But now, some of the red lights on Interstate 17 ramp meters will also play a role in the wrong-way vehicle detection system the Arizona Department of Transportation is testing.
When the thermal camera-based technology that is in place along 15 miles of the I-17 in Phoenix detects a wrong-way vehicle, the system will now also turn on the red lights in nearby entrance-ramp meters to try to prevent "right-way" traffic from entering the freeway, ADOT said.
The red lights on the entrance ramps are programmed to turn on within 3 miles of a detected wrongway vehicle, ADOT said. If the vehicle continues to drive along the freeway, additional red lights on entranceramp meters will be activated.
ADOT said the red lights are set to return to their normal mode, including turning off when it is not rush hour, after the system confirms that the wrong-way vehicle is no longer in the area.
“As we test the overall wrong-way vehicle alert system and research its performance over the next several months, it’s important to note that the ramp meter red lights are one of several countermeasures,” said Susan Anderson, ADOT’s systems technology group manager. “The ramp meter lights are traffic signals, so I-17 drivers on entrance ramps should be prepared to stop if the light is a solid red, no matter what time of day.”
The wrong-way detection system on the I-17 — the first of its kind in the nation, according to ADOT — uses 90 thermal-detection cameras positioned above exit ramps and along the freeway's main between the Interstate 10 "Stack" interchange near downtown and the Loop 101 interchange in north Phoenix.
According to ADOT, when a wrongway vehicle is seen entering an offramp, the system triggers an illuminated "wrong-way" sign to try and get the driver's attention. The system also alerts to ADOT's Traffic Operations Center and the Arizona Department of Public Safety, so traffic operators can warn other drivers via freeway message boards, and state troopers can respond faster than relying on 911 calls.