I used to believe that the traffic lights are controlled by a person sitting in some office near it. That person is in front of a lot of TV monitors so he could see when to push the right buttons for red, yellow and green.
A childhood belief about traffic lights

others believed things like this
- i used to believe that red yellow and green meant "ready, set, Go!" on traffic lights..— cabagona
- On motorways the person at the front of the traffic had set out
first— andy - when i was about 5-8 i used to believe that oompa loompas lived in traffic lights and controlled the lights!!— ~wierd ~
- I used to believe that God controlled the traffic lights. He would decide when it was everybody's turn to go.— Amanda
- i used to beleive that elves controlled traffic lights.— Jessica
- When I was little, I was thought that little elves controlled the traffic lights..— Rosie