Quote:
Originally Posted by trebuchet03
I've noticed in Orlando that there's two sets of road sensors... One about 50-100 yards from the light, and another set at the light itself... I don't know if they're using it to figure out when traffic is coming, or when the light has backed up cars up to that point  But they're only in the heavily used roads... |
We have the same here, with roads that have speed limits from 60-70 and traffic lights. Of 3 sensors, I think the first 2 sensors calculate the "Yellow-Duration" based on speed of the approaching high-speed traffic (based on the constant of distance between the pads and the trigger of the vehicle passing each). The final pad probably detects if the vehicle has stopped and is waiting, and also the final calculation for the "Yellow-Duration" if the vehicle has not slowed. Many times, I've hit that first pad and the light has turned yellow (if I continue, the yellow holds until I clear the intersection -- if I slow to stop, the red is triggered sooner).
Local observations...
RH77