The contact owns a 2019 Lexus RX350. The contact stated while his wife, was reversing in the driveway she hit the retaining wall. The driving alarms failed to engage and alert. The driver depressed the brake pedal however failed to respond and was depressed to the floorboard. The emergency brake failed to engage. The vehicle rolled down the hill and crashed into some unknown objects in the driveway. There were no reported injuries, air bag deployment, police report or fire. The vehicle was drivable. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was notified however, no further assistance was provided. The failure mileage was approximately 30,000.