Traffic light control circuit will lead you in the right direction

This project details a traffic light control circuit that features twenty open collector outputs that turn on one at a time in a continuous sequential manner. The circuit makes use of the 74LSxx family of TTL integrated logic devices. The circuits are designed to drive light emitting diodes or low current, low voltage incandescent lights but can also drive other loads of up to 80 milliamps. Check out the details at the link below.

Traffic Light Control Circuit, via Electronics Lab