The questions "how much visual information from the road is required for proper driving?", and "how do people cope with a visually ambiguous road configuration?", were explored in an advanced driving simulator. Sixteen young and 16 elderly drivers completed two test rides on a rural road that was divided into five sections of 2 km, at each section a road element (e.g., delineation, roadside marker) was added or removed. During the rides, performance (lateral position, speed) and heart rate were recorded continuously, and before transition to a new section drivers gave a rating on invested effort and on visibility of the (previous) road course. The experiment's goal was to determine whether a shift in driving behaviour could be noticed at a certain amount of visual information. The main threshold found, for both age groups, lies between roads with ‘no delineation on the road surface at all' and ‘a centre-line'. Elderly drivers, however, appeared to need the visual aid of the centre-line to a greater extent than young drivers, and in general they drove slower and regulated their information input in this way. A visually ambiguous road situation concluded the experiment. The participants drove on a centre-lined road towards a junction where the road forked to the left and right. The left-hand road was a road without delineation but with lampposts, the right-hand road was a continuation of the centre-lined road without lampposts. In particular elderly drivers were confused by this situation and chose the road with lampposts more often. This finding supports the assumption that with increasing age people are more easily confused by ambiguous cues. (Author/Publisher)
Abstract