Introduction
The public's understanding of the traffic signal system functions can improve driving habits by reducing speeding and the associated traffic accidents. The more drivers know about the operation of traffic signals, the less they will be frustrated when waiting for signal changes.

Garrett A. Morgan invented the traffic signal during the 1920's. The very first traffic lights did not even have lights at all. They had signs that said stop and go.

How does a traffic light work can be a good subject for a science project.