• (Road 1) that has one direction to the right side. And it cannot go anywhere else. • (Road 2) that has one direction to the left side. And it cannot go anywhere else. • (Road 3) that has one direction to the upside. And cannot go anywhere else.
When road 3 traffic light is green, traffic lights 1 & 2 should be red so road 3 cars can drive the other way.