This study evaluates the comfort benefits of adjustable pedals by determining their effect on the distance between the occupant and steering wheel, occupant posture and foot kinematics. For the study, 20 volunteers were tested in a small and large vehicle equipped with adjustable pedals. Twenty volunteers were tested in a small and large vehicle at 3 pedal positions: normal, comfortable and maximum tolerable.
In the small car, the decrease in ankle-to-steering wheel distance between the normal and comfortable position was higher in the short-statured group than the medium group. The mean change in chest-to-steering wheel distance was about 50 mm in the medium and in the order of 40 mm in the short group. The seatback angle increased by 2° in the medium group and decreased by 3° in the short group.
In the large car, the decrease in ankle-to-steering wheel distance between comfortable and the normal position was about 70 mm in the short-statured and medium group. The corresponding change in distance between the steering wheel and driver’s chest was 38 mm for the short-statured group and 32 mm for the medium group. The tall group did not extend the pedals since their seat track was in its rearward limit in the normal position.
In both vehicles, various factors influenced the use of the adjustable pedals. These factors included visibility, kneesteering wheel contact and arm posture. The videos revealed a reduction in heel lifting between the normal and comfortable/maximum tolerable positions for the short-statured group. The results obtained in this study show the usefulness of adjustable pedals, in particular for short-statured drivers in large vehicles, and provide quantitative information that can be used as guidelines for future pedal designs.