Human Factors Considerations for a Combined Brake-Accelerator Pedal

Abstract

The results of a series of nine experiments over a three-year period arc reported, Experiments One through Six. previously published, indicated that a pedal which actuated an accelerator upon depression of the toe and actuated the brake upon depression of the heel saved 0·2 sec (one car length at 60 mph) over the conventional separate controls.

Experiment Seven investigated the effect on reaction time of: the angle the pedal made with the floor; the force required to actuate the brake control; the force required to actuate the accelerator control; and the seat reference distance. The minimum time was 0·241 see. Little penalty resulted when the pedal angle was between 30 and 40°, brake actuation force was between 13 and 21 lb, accelerator actuation force was between 4 and 8 lb, and seat reference distance was between 4n and 55% of the person's height.

Experiment Eight investigated the effect on reaction time of; the angle the pedal made with the floor; seat height from the floor; the angle of twist of the pedal; and seat reference distance. The minimum time was 0·284 see. Little penalty resulted when the pedal angle was between 30 and 45^°, seat height was between 8 and 10 in. from the floor, the angle of twist was between 90 and 104^°, and the seat reference distance was between 40 and 50% of the person's height. Experiment Nine investigated, for older subjects, the effect on reaction time of; pedal angle; seat reference distance: and the angle of twist of the pedal. The reaction time of the optimum combination was 0270 sec. The savings of 0-18 sec (versus conventional) for student subjects increases to 0·23 sec for subjects aged 60. Instruction time averaged 30 sec.