The contact owned a 2021 Tesla Model Y. The contact stated that while driving approximately 70 mph but doesn't recall; the vehicle began shifting from left to right for 5 - 10 seconds when another vehicle approached the passenger side of the contact's vehicle. The contact attempted to disable the autopilot by depressing on the brake pedal and maneuvering the steering wheel however, the vehicle would not allow the contact to control it and it spun around and hit the median wall on the highway. Medical attention was received on the scene for the contact's sister, who was a passenger. A police report was filed. The vehicle was towed to a Tesla repair center, where there's an ongoing investigation. The manufacturer was made aware of the failure and informed the contact that they would respond within 6-8 weeks after the investigation. The failure mileage was approximately 300.