I used to believe that traffic lights were controlled by groundhogs (or some similar animal) that had been trained to make the lights change when it felt cars go over the road.
A childhood belief about traffic lights

others believed things like this
- 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
- I thought traffic lights were controlled by little men who lived inside them. Anon
- I believed that traffic lights had police officers inside them, turning the lights on and off...— CrowHeart