Car Accelerates On Its Own problems of the 2009 Chevrolet Traverse

2009 Chevrolet Traverse. Consumer states unintended acceleration the consumer stated as she was driving her son's vehicle, she accelerated to move to the left lane, when all of a sudden she had no control of the vehicle's speed. She attempted to brake, but to no avail. When she gradually removed her foot from the brake, the vehicle accelerated to 80 mph. The consumer put the hazards on and placed both feet on the brake as she tried to hold down the speed. Finally, after two miles of riding the brakes, she was able to exit on the ramp and put the vehicle in neutral and then in park where the rpm's finally went down. The vehicle was inspected and stayed at the dealer for three weeks. However, they were unable to find a problem.