I feel the amber lights in some cities are dangerously short. How long should a yellow light be?
It would depend on the allowed speed of the traffic.
In sothern cali I know if the speed limit is 30 mph...the amber light is 3 seconds....50 mph....5 seconds
The regulation is modified by city municipalities. Some are longer than others for obvious reasons. Intersections with no turn light will run amber lights longer for those sitting in the intersection waiting to turn against traffic.
According to the red light camera laws they have to be 3 full seconds to qualify for the red light cameras. An independant study shows that 4 second yellow lights are the most effective in lowering accidents...the laws of three seconds for the cameras are just to get revenue. Anything over or under 4 seconds is not an effective yellow light
Yellow lights vary in duration. Traffic lights along 25 MPH residential area roads do not need to be nearly as long as the ones placed at the junction of two 65 MPH state highways, for example. There are some basic formulas used by engineers to determine starting norms.
