Back then, many of us who worked in fields like ergonomics, human performance and psychology suspected that these unintended-acceleration events might have a human component. We noticed that the complaints were far more frequent among older drivers (in a General Motors study, 60-to-70-year-olds had about six times the rate of complaints as 20-to-30-year-olds), drivers who had little experience with the specific car involved (parking-lot attendants, car-wash workers, rental-car patrons) and people of relatively short stature.
Several researchers hypothesized how a driver, intending to apply the brake pedal to keep the car from creeping, would occasionally press the accelerator instead. Then, surprised that the car moved so much, he would try pressing harder. Of course, if his right foot was actually on the accelerator, the throttle would open and the car would move faster. This would then lead the driver to press the “brake” harder still, and to bring about even more acceleration. Eventually, the car would be at full throttle, until it crashed. The driver’s foot would be all the way to the floor, giving him the impression that the brakes had failed.
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the driver does not really confuse the accelerator and the brake. Rather, the limbs do not do exactly what the brain tells them to. Noisy neuromuscular processes intervene to make the action slightly different from the one intended. The driver intends to press the brake, but once in a while these neuromuscular processes cause the foot to deviate from the intended trajectory — just as a basketball player who makes 90 percent of his free throws sometimes misses the hoop. This effect would be enhanced by the driver being slightly misaligned in the seat when he first gets in the car.
The answer to the second question is that, when a car accelerates unexpectedly, the driver often panics, and just presses the brake harder and harder. Drivers typically do not shut off the ignition, shift to neutral or apply the parking brake.