Learn How to Trigger Traffic Signals

Bicycles are vehicles under Utah law and must follow the rules of the road, including stopping at red lights.

If there are motor vehicles also waiting at the red light -- in a travel lane going the direction you want to go, you will get a green light when it is your turn. Although bicyclists often run red lights, this is a considerable source of animousity between motorists and bicyclists. You are an ambassador for bicyclists' rights to be on the road. As a matter of bicycling ethics, bicyclists should obey the law.

However, if there is no motor vehicle waiting at the signal with you, you may be frustrated that the light will not turn green for you. At such traffic signals, bicyclists can often trigger the green light -- if you know where to position your bicycle.

Video detection

At some traffic signals, you will see small cameras up near the signals. The cameras should detect bicyclists who are waiting in a bike lane or in the travel lane. The cameras are set to ignore right-turning cars. If you are in the right-turn area, you may not be detected. If there is no other traffic on the road, try stopping your bicycle in the middle of the through lane to get a green light.

Loop detection

If you can see circular patterns or other patterns of a metal wire just under the road surface, position your bicycle with the wheels and crank over the edge of the circle, or over the wires for other patterns. These wire, called "loops," detect metal; the bicycle's smaller amount of metal must be very near the wire to trigger the light. If you have cleats on your shoes, try putting your cleat right on the circle of the loop.

Timed detection

During rush hour, most traffic lights in the City are timed by a computer, independent of vehicle detection.

Pressure plates

It is a common urban legend that "bicyclists don't weigh enough" to trigger the traffic signals. Pressure plates, which detected the weight of a vehicle, were indeed used historically; however these have not been in use for many years. In Salt Lake City, the last pressure plates were removed in the late 1970s or early 1980s. If you are looking at a circle or square in the pavement, that is actually a loop detector (as above), not a pressure-sensitive area.