Abstract
This paper deals with the task of driving in relation to the design of vehicles and roads. Following a discussion of the possible mental processes involved, certain limitations inherent in the driver's perceptual systems which merit the attention of road engineers are noted. By means of an illustrative example the difficulties confronting a driver as he tries to cross a particular road junction are described. It is shown that, in spite of excellent visibility, a driver is under considerable stress and this is reflected in a high accident rate.