The purpose of this SAE Recommended Practice is to present design recommendations for the direction-of-motion of hand controls found in passenger vehicles, multipurpose vehicles, and trucks. These recommendations are based on recent and past human factors research and are important considerations in the design of control layouts.

Background

Drivers develop expectations regarding the operating motions of various types of controls as a result of their accumulated experience with automotive and nonautomotive controls. To simplify the operation of controls for drivers, the direction-ofmotion to operate these controls should conform to these expectations or stereotypes. Failure to conform to direction-ofmotion stereotypes can lead to actuation errors, longer operating times, and an increase in driver workload.

A number of past studies have addressed the issue of direction-of-motion stereotypes for various automotive hand controls (1, 2, 3, 4, 8). These results indicate that the strength of a stereotype varies with the control configuration (control type, location, orientation, and mounting plane). SAE has recently completed research (6,7) aimed at broadening the scope and generality of the previous findings by addressing other control orientations, including controls mounted on stalks and on inclined surfaces. Some specific control functions such as power windows and power mirrors were also studied. The SAE study demonstrated that stereotype strength is not related to driver age, gender, or handedness. This document is based on the SAE study, past research, and general human factors principles (10). This document supersedes Figure 1 of SAE J1139 (9).

Control labeling and tactile or shape coding are not addressed in this document; however, previous research (5) has shown that appropriate labeling and coding can improve the accuracy of control use.