Traffic Signal Detectors Throwing You for a Loop?

Most intersections in OC have detectors to let the signal know someone is waiting. The most common is a loop of wire in the road that acts like a metal detector. California requires these sensors to detect one bicycle wheel – metal or carbon – but shifting pavement and rain degrade function. A coat of asphalt or slurry seal can reduce sensitivity and hide the location of the wires.

Here is what you need to know about getting a green light:

  1. The sensors are usually BEHIND THE LIMIT LINE. If stop in a crosswalk, you have broken the vehicle code and are likely past the sensor loop.
  2. They can pick up one wheel, but both wheels (or the wheels of more than one bike) should be on the wire.
  3. If the loop does not detect you, and no car or truck comes along, the best option is to use the crosswalk button. If you are already waiting in a left turn pocket, carefully cross to the corner on your left. Technically, you can only run the light if it is inoperable. Not sensing you does not mean inoperable in some cities, and people have been cited. You may prevail in court, but what a waste of time!
  4. Tell some one! The loops are adjustable, so contact the local city Director of Public Works. In unincorporated areas, contact OC Public Works. For freeway intersections, contact Caltrans. Copy us at, and we will try to help.
How to use a traffic sensor loop

Credit: California Association of Bicycle Organizations