I was backing my Porsche out of my garage with my foot on the brake. The car backed slowly as expected for a few seconds, then flashed a red display on the dashboard (see attachment) warning of an electric system error. It immediately self-accelerated in reverse at a high rate of speed across the street. The brakes did not work. Within 4-5 seconds it hit my neighbor's house and crashed into a room. I was trapped in the car and had to have the fire department get me out. The video police downloaded from the camera over my garage confirmed my account to them (as written above). I can provide the video if you would like to have it. A DMV examiner told me that about a year prior, around June 2022 an exactly similar accident was referred to him involving a Porsche Taycan accelerating out of control in reverse (see attachment).