The Effects of the Steering Wheel to Pedal Relationship on Driver-Selected Seat Position

A small car packaging study investigated the effects of the wheel to pedal relationship on driver selected seat position. The horizontal seat positions of sixty subjects stratified by stature and sex to represent the general driving population were recorded in package configurations with three pedal to wheel distances and three pedal-wheel relationships to the interior surface of the vehicle (windshield header, pillar, glass and instrument panel surface). Subjects utilized comparable amounts of seat travel in all configurations. Pedal to wheel distance and pedal-wheel relationship to the interior surface of the vehicle affected seat position independently. When the heel point location was held constant and horizontal wheel location was moved forward in 45mm increments, the seat position distributions shifted forward 5 to 10mm. Likewise, when the heel to wheel relationship was held constant but moved forward in 45mm increments in relation to the interior surface of the vehicle, the seat position distribution shifted forward 13 to 16mm. All distributions reasonably approximated normality. Shifts of such magnitude were found to be statistically different but in reality represented less than one seat detent of travel (22mm in GM vehicles). In addition, it appeared that in packages with tight heel to wheel distances, subjects gave greater priority to comfortable leg rather than arm reach when positioning their seats.