One or more technically minded scofflaws are driving around San Luis Obispo with gizmos that make red lights at busy intersections turn green, screwing up traffic patterns and slowing down the response times of ambulances and fire trucks.
The devices shoot infrared signals at receivers mounted on key intersections around the city, signaling them to change. While the signal-changers have been used by emergency vehicles for decades, they're illegal for regular folks. They can be bought on the Internet, however, and instructions for making do-it-yourself versions are available.
Nobody knows for sure how many people in the area have the transmitters, but they're prevalent enough that Tim Bochum, deputy director for SLO city public works department, witnessed somebody using one while he was investigating reports of the problem.
He was at the intersection of Marsh Street and Johnson Avenue, monitoring the traffic signal.
"We actually saw it go into preemption with no emergency vehicles in the area as we saw several cars driving through," he said.
The city has since disabled that receiver, but it's also seen problems at the intersection of California and Foothill. Jim Shivers, a spokesman for Caltrans, said the state has disabled other signals along the Highway 1 portion of Santa Rosa Street. He declined to name the intersections.
"Our view is that this could pose a potentially serious safety hazard for people driving," Shivers said. "Imagine if an ambulance or fire truck is approaching an intersection. Imagine somebody else coming along in their car from a different direction and tripping that green back to a red."
Police haven't caught anyone with the "signal preemption" devices yet, but Bochum said city staffers are working with police. Using the devices without permission is a state and federal crime, punishable by jail time and fines of up to $10,000 if someone is injured as a result of the tampering.
In the meantime, the city is working to reprogram the receivers, or buy new ones that can't be pre-empted. Bochum said he's seeking a grant.