Went through automated car wash. Proceeded to lane for towel drying. Car suddenly unintentionally accelerated. Hit rear passenger side of parked car and also collided with the fence that ultimately stopped my forward motion. The car passed across two side walks and one side street during this event. No pedestrians or cross traffic was present or this would have been catastrophic. There were no previous warning signs of this event. My insurance company was notified and inspected the vehicle. A formal complaint was filed with Subaru of America and we are still waiting for them to inspect the vehicle. They have authorized repair of the vehicle prior to them seeing it.