Are you sitting at a red light and the light isn't changing to green? Try flicking on your high-beams. There are a lot of red lights that have photo-sensors that detect increased luminosity and control traffic flow. The sensor is sitting above the red light and is fairly small.
I talked to a signal guy once a long time ago. he said flash a light at the sensor 12 cycles a second this cause it to change like an ambulance or fire truck, almost instantly.