i was driving and at a complete stop at a light. And all of a sudden the car started rolling all by itself. almost hitting the semi in front of me i was scared put the car in park and shut the car off.
did you have your foot on the brake pushing down? or just resting slightly on it?
did the pedal go to the floor?
are you sure there was not a water bottle or something on the floor behind the brake pedal?
Needs to be looked at by a repair shop or the dealer.
How long have you been driving?