The contact owns a 2024 Hyundai Tuscon. The contact stated that while driving 55 MPH the vehicle rear of a second vehicle during the failure the no safety features had activated including the airbag, collision avoidance features. During the incident the vehicle collided with the same vehicle twice although the brake pedal was pressed. During incident the driver sustained neck, shoulder and back injuries and was unconscious and transported to the hospital. A police report was taken at the scene. The vehicle was destroy the towed away. The contact was informed that the safety sensor had failed during the incident. The manufacturer was notified of the failure, but no assistance was offered.The failure mileage was 5,000.