NHTSA Complaint #11533410 — 2010 BMW M3

Parked on a slight hill, shifted out of drive and applied the ebrake by pulling up firmly. Unbucked my seat belt, opened the door, and got out of the vehicle. Left the door open to go in my house, grab my wallet, and come back. The car stayed in neutral instead of shifting into park which should have happened but multiple components of the car failed to detect me exiting (door latch sendor, software, seat sensor, seat belt sensor). Leaving the car in neutral meant the parking brake was all that was available to hold the car. As it turns out, the electronic brake was not strong enough to do so, and the car rolled down the hill hitting another car, pushing that car into a structure and causing my car to be totaled. This never happened before but due to car not shifting into park with exiting, the vehicle became a rolling hazard putting all people and property around it at risk. I did not hear or see any warning messages as I had exited the car as I had always done previously. I should not have to turn off the car (press power on/off) to engage park or there should be a "park" button like most cars. Given there is no labeled park, the system gives you no indication of what steps you have to take if autopark doesn't engage. My car has been totaled and released to copart. It may be available for inspection from them.