Ergonomics of steering wheel mounted switch-how number and arrangement of steering wheel mounted switches interactively affects performance

Recently, the use of steering wheel mounted switches has been receiving attention. Such switches allow a driver to maintain his or her focus on the road. If the number of steering wheel mounted switches or their arrangement is improper, the advantage of using them may be diminished, and many operator errors may occur. The objective of this study was to examine how the number of steering wheel mounted switches and their arrangement interactively affected a driver's performance. The participants were required to press a specified switch while performing a first-order tracking task. The number of steering wheel mounted switches affected the reaction time in the switch operation task. With regard to the method of arranging the steering wheel mounted switches, the cross-type arrangement was more effective than a vertical-type arrangement. The cross-type arrangement with three steering wheel mounted switches provided the best performance and highest psychological rating. Relevance to industry: Cars equipped with steering wheel mounted switches are increasing. However, the number and arrangement of switches differ among automobile manufacturers, and there are no specific design guidelines on the number and arrangement of steering wheel mounted switches. Such guidelines would contribute to safety and efficiency by determining the optimum number of steering wheel mounted switches and their arrangement. Consequently, such a study would be expected to result in a reduction in driver errors and vehicle accidents.