July 3, 2006 -- The traffic light at the end of the Krumkill Road exit from Route 85 southbound has always been equipped with a sensor to allow the traffic to flow smoothly off of Route 85. Recently traffic has become very congested in this area -- so much so that the traffic backs up the entire exit well onto Route 85.
There was a problem with a sensor -- though it wasn't the typical type of sensor we've become familiar with at regular intersection signals.
This signal is equipped with a force-off loop near the start of the Route 85 exit ramp, about 500 feet from the stop bar painted on the pavement, said state Department of Transportation spokesman Peter Van Keuren.
If a line of cars extends down the ramp and a vehicle rests over this loop for more than four seconds, the computer controller for the signal will override the normal phasing and give a green light to motorists lined up on the ramp.
"We do this to avoid having the end of the vehicle queue extend out onto the mainline of Route 85, where there is a 55 mph speed limit and a vertical curve limiting sight distance to the ramp," Van Keuren said.
Because of inquiries, DOT dispatched a signal crew to the location and found that the force-off loop had stopped working. The loop needs to be replaced, Van Keuren said, and to ease the backups in the meantime, DOT workers modified the signal timing to allow longer green times on the off-ramp.
Van Keuren said a signal maintenance crew will install a new loop this week.
