[ericfranklin]

I've seen the induction loops "presence" sensors too. One near where I used to live would never change to green unless the sensor was triggered, but wouldn't register until your car was beyond the crosswalk, nearly in the intersection. That means if someone in front of you stopped where they were supposed to, the light would never change.

I suppose there is bias though, in that people don't notice as much when traffic lights are operating efficiently.