Locating in car controls: predicting the effects of varying design layout

This paper describes two studies which aimed to understand the relative importance of different key design parameters on the location of in-car controls. In study 1, 18 participants followed a lead vehicle within a fixed-base driving simulator and at specific points were asked to find and then select a specific control from an array of controls on an in-car touch screen. The control layouts varied according to: the number of controls; control size; and control spacing. Results indicated that the number of controls was the dominant factor, having a clear relationship with task times, visual demand and subjective ratings. In study 2, 20 participants carried out a similar driving task within the simulator, but in this case the layouts for controls varied according to total cluster size and arrangement (how many controls in the horizontal versus the vertical plane). For this study, there was evidence that the vertical dimension had a clear relationship with task times, visual demand and subjective ratings. Recommendations are given regarding the impact of alternative control design layouts on driver performance and ratings.