[jerezzprime]

For this situation, and similar ones, there are simple solutions. For example, in this situation, the timer should always be running (and resets when the light changes). When a car triggers the sensor, the light should change if the timer is > N. If the timer is not there yet, wait until timer is N.

No AI required, just basic thoughtfulness and requirements gathering.

[WalterBright]

The trouble with the street sensors is that your car has to come to a stop before it is detected. Stopping and starting cars consumes a great deal of gasoline.

Contrast it with the flow achieved when there's a traffic cop managing an intersection. It's an enormous improvement.