Monday, April 1, 2013

Bicycle Detection at Traffic Signals

Sometimes an on-demand/traffic-actuated traffic signal does not change to green for people on bikes. This is more than annoying. It can be dangerous to proceed through a red traffic light, right? To increase your chances for triggering the light to change it is important to be correctly positioned at the intersection so that the traffic signal senor system can "see"/detect you. This is important both for the camera and for the in-pavement sensor systems; placement matters. 

Many traffic signal lights only operate on-demand, either by pushing a pedestrian crossing button or by the presence of a vehicle or bicycle at a very specific location at the intersection. For the systems that use devices in the pavement, it can sometimes be difficult on a bicycle to find the "sweet spot" that will trigger detection. Some cities place a "bicycle sweet spot" pavement marking to help with this. Without a sweet spot marker to help with detection we can look for the pavement cut marks to help find the best spots to stop over.

Below is a graphic depiction of how a person can best position themselves on their bicycle to cause various types of in-pavement on-demand traffic signal detectors to actuate/change a traffic signal; proper positioning matters. Proper placement for an in-pavement sensor will also work for camera detection systems. 

The illustration creator, Dan Gutierrez, provides this through the California Association of Bicycling Organizations (CABO).

There's lots more that could be said about this subject; one being that when you find a location where an on-demand traffic signal will not trigger for you, report it to the responsible city, county, or State agency. "Squeaky wheels get the grease."

Click here for more information about vehicle detectors. 

- Jim Baross, SDCBC Spokesperson and Advocacy Committee Chair


  1. Good to Know about car street at light detectors (now I do know where I need to be in order to change the light); normally if the red light would not change green for myself as a road cyclist, I would use the direction I am going, it's greed light, but as a yield, move with caution from any oncoming traffic the opposite direction.

  2. Thank you so much for providing such helpful information. This is really informative and I will for sure refer my friends the same. Thanks
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