Sudden unintended acceleration (SUA) is the unintended, unexpected, uncontrolled acceleration of a vehicle, often accompanied by an apparent loss of braking effectiveness. Such problems may be caused by driver error (e.g., pedal misapplication), mechanical or electrical problems, or some combination of these factors. The US National Highway Traffic Safety Administration estimates 16,000 accidents per year in the United States occur when drivers intend to apply the brake but mistakenly apply the accelerator.