New traffic device keeps green lights on longer

Highway authorities plan to add the magnetic sensors to 100 high-speed intersections a year until they have the state covered. An intersection at a road with a speed limit of 40 mph or higher is considered high speed.

The Associated Press

9/29/2008

LAYTON, Utah — The Utah Department of Transportation is installing magnetic vehicle sensors at high speed intersections to help motorists trying to decide whether they should abruptly stop on a yellow traffic light.

It's called the dilemma zone, the length of 500 feet to a set of traffic lights, where motorists whizzing along have to decide whether to run a yellow light before it turns red — or start braking.

UDOT spokesman Adan Carrillo says the dilemma zone is a big factor in many collisions.

"Everyone knows what it's like to kind of be caught in between on a yellow light," Carrillo said. "Do I go or do I stop? This technology will help eliminate that."

The technology detects vehicles in relation to the stop line and how fast they are traveling.

If necessary, the magnetic sensors will let a green light remain on longer for approaching traffic.

The sensors are housed in a box affixed to traffic-signal arms or street light poles.

Yellow lights can be a problem for motorists with different agendas, said Dave Kinnecom, director of UDOT's Traffic Operations Center.

"Two people see the same yellow light, but the person in front might decide to stop, while the person behind might have been set on going," Kinnecom said. "Hopefully, this will stop some of those rear-end collisions."

The technology has been installed at selected intersections throughout Weber and Davis counties.

Still, "people should obviously continue to practice good driving behaviors," Carrillo said. "Just because we have this new technology doesn't mean you should start punching it through the lights."