I used to believe that when you took your foot off the gas, the brake lights would go on. I'm still not completely convinced this isn't true...how would I know? I can't see the back of my own car while I drive :P
A childhood belief about cars

others believed things like this
- When I was a kid I was completely convinced that Sade's "Smooth operator" was "Ooh of the red eye".— Brookstar78
- I used to believe that echos were actually the sound going completely around the world and coming back to you.— kyle
- Because of cartoons, I thought that to drive you'd just turn the steering wheel back and forth constantly. — Mitsuki
- I used to belive that if i put my foot in my mouth, I would get foot-and-mouth illness— Emily Sathrota
- I believed that traffic lights had police officers inside them, turning the lights on and off...— CrowHeart
- when i was about 5-8 i used to believe that oompa loompas lived in traffic lights and controlled the lights!!— ~wierd ~