The contact owns a 2019 Tesla Model X. The contact stated while driving approximately 30 mph in the carpool lane, the brake pedal was applied however the vehicle failed to stop and crashed into an unknown vehicle. The contact mentioned the brake alert feature failed to engage. There were no police reports filed, injuries, fire or air bag deployment. The contact called the local dealer but the vehicle was not diagnosed or repaired. The manufacturer was notified of the failure. The approximate failure mileage was 20,000.