Officials urge drivers to pull up to stop bars to activate traffic light sensors

KENTUCKY (WFIE) - Officials with the Kentucky Transportation Cabinet have sent out a reminder to drivers that long waits at traffic signals could be avoided by making sure you pull all the way up to the “stop bar” at intersection.

They say modern traffic lights are no longer controlled primarily by timers, but instead by sensors imbedded in the pavement to detect the presence of vehicles.

These sensors, technically known as inductance loops, are located directly behind the “stop bars,” which are the thick white lines on the pavement. When the inductance loop senses a vehicle stopped for a red light, it triggers the control box to change the traffic light from red to green.

When drivers stop well short of the “stop bar,” or pull past the “stop bar” into the intersection, the inductance loop cannot sense the presence of the vehicle and thus will not trigger the light to change.

Officials say traffic light systems still have timers built into them for occasions when the loop sensors are not working due to construction or malfunction, so that traffic flow can be regulated at intersections controlled by traffic lights.

In areas where no construction is taking place, drivers who suspect that a loop sensor is not working properly are asked to contact the Department of Highways to let them know.