The present design of automotive braking systems requires the driver to move his leg to another control and actuate it. In addition, the leg /the slowest body member/ is also allocated the acceleration task and these two tasks are performed on separate controls. A simple reaction time experiment under four different conditions showed the considerable improvement /a reduction of 0.2 sec/ that can be made over the existing procedure with such a minor change as designing the brake to be actuated by the left foot. A hand-operated brake actuated by squeezing a portion of the steering wheel would also reduce reaction time by 0.2 second. At 30 mph this is equivalent to 9 ft and at 60 mph, 18 ft. The primary disadvantage of separate controls is the physical distance separating them. A device which combined both controls would eliminate the time required to move between the controls, and the possibility of moving and missing the other control. A combined brake and accelerator pedal was obtained. Pressing with the toe activates the accelerator and depressing the heel activates the brake. An interlock prevents simultaneous operation. Reaction times were plotted vs age of subjects for both types of controls. It is felt that this combined control probably should be installed along with the conventional brake pedal.
Samenvatting