May 29, 2012 — The next time you’re wondering why you’ve waited through two red lights when you’re certain the signal should have turned green, Mayor David Perkins suggests you check your position.
“When cars pull too far over that big white stop bar at an intersection, it’ll probably sit there for two or three lights, or until more vehicles come along to trigger the timing loop,” Perkins said.
The timing or inductive loop is a long piece of wire embedded in the asphalt and then sealed with a rubbery substance.
It’s always placed just before that white bar in the road that indicates where you should stop. The problem, Perkins said, is that too often cars creep over that line.
An inductive loop emits a type of electrical field. When a car comes to rest on top of the loop, it disrupts that field which sends a message to the signal box that a vehicle is present.
Normally, the light will change soon after a vehicle is detected. When a car overshoots the loop, and part of it comes to rest on or over that white bar, the field is not properly interrupted. That’s when you sit.
“The key is to stop behind that bar,” Perkins said.
For a brief video demonstration of traffic signal loop installation go to http://www.youtube.com/watch?KvzJn09DqaM
Noelle Hunter can be reached at nhunter@themoreheadnews.com or by telephone at 784-4116.
