The aim of this study was to propose an effective method for displaying driving environment and properly transmitting this to drivers. The display was designed by changing two types of proximity, that is, the proximity of the display and the proximity of the task itself. The proximity of the display was controlled as the type of the display or the distance between two displays. The proximity of the task was controlled as the difference of two tasks performed on the two displays. More concretely, the similar proximity of the task was either two analogue tasks or two digital tasks. These two proximities were all within-subject variables. The participants (a total of eight graduate or undergraduate students) were required to carry out simultaneously a simulated driving task and a judgment and reaction task of the display information controlled by the two proximity factors above. The performance measures were tracking error in the simulated driving task and percentage correct and reaction time in the secondary judgment and reaction task. As a result, it has been demonstrated that the performance under the dual task condition obeys the predicted outcome by proximity compatibility principle.