Its really a parking gear, or at least one tooth of it. If you're going too fast it just doesn't drop in, but it does make a real weard sound. When the car slows enough it will drop in and that speed is fast enough to break it. When I tried it I was on ice so all it stopped was the drive train.

I also found out how to stop a car on ice...

nice, i have no drinving license but my dad has a lot of experience he is a truck driver too and he has had a cursus(lesson) how to drive with a car on ice at things like that, its really fun on ice ( only if u can drive good!)