Amazing as it sounds, there are people who drive automatic transmission cars with two feet. They typically drive with the left foot resting gently on the brake pedal, with the belief that they can brake more quickly than if they move their right foot from the gas to the brake. They of course neglect the possibility that they will overlap, and will reduce the effectiveness of the brakes.
It is likely that NHTSA will mandate, or Congress will pass a law which requires that automakers who use Electronic Throttle Control Systems (ETC) must have brake override logic, similar to the software update that Toyota is releasing as part of its recent unintended acceleration recall.
As this feature becomes more widespread, two-foot driving will become a little bit more difficult. The two-foot driver will find that if they overlap brake and throttle pedal application, that they will get abrupt reduction in engine torque, and therefore more abrupt deceleration, as the ETC system slams the throttle closed to reduce engine power. In order to drive smoothly, they will have to take the time to lift off of the throttle before pushing the brake, giving up much of the perceived advantage of two-foot driving.
