The contact owns a 2023 Tesla Model Y. The contact stated that while pulling into a parking space with the brake pedal depressed, the vehicle unintendedly accelerated and struck an occupied parked vehicle ahead. Upon shifting into Reverse (R), the failure recurred, causing the vehicle to strike the front bumper of a parked and unoccupied USPS truck, which then struck a parked, unoccupied vehicle. The contact engaged the electric parking brake to stop the vehicle. The contact stated that the forward collision avoidance system failed to engage to prevent the collisions. The front driver's side air bag failed to deploy as expected. The vehicle sustained rear-end damage. The vehicle was towed to an auto collision center, where a superficial diagnostic inspection was performed, and the contact was informed that no failure was found. The manufacturer was notified of the failure and referred the contact to a Tesla Service center and to the NHTSA Hotline for assistance. The failure mileage was 30,616.