My car was parked in the driveway with the engine running. The engine was then turned off from outside the vehicle using the start/stop button. Once the engine stopped, the car moved backward down the sloped driveway and struck a pickup truck that was parallel parked on the street. I then entered the vehicle and attempted to shift into drive, but a warning appeared indicating the hybrid system was off and instructing me to put the car in park. Multiple attempts were made to drive the car forward, but instead, it was driving in reverse. The car would not move forward for approximately five minutes. I eventually turned the engine off and restarted it after a couple of minutes. After restarting, I was able to drive the car off the street.