IMPROVING DRIVER PERFORMANCE ON CURVES IN RURAL HIGHWAYS THROUGH PERCEPTUAL CHANGES

Abstract

The perceptual processes involved in curve negotiation were studied in road and laboratory tests. Visual search patterns and motor control movements were measured on the road, and curve psychophysics, information processing abilities and susceptibility to visual illusions were studied in the laboratory. The major results of the study were (a) traditional measures of curve length and central degree were unrelated to accident statistics, drivers' perception of curvature, and drivers' tendencies to decelerate before the curve. (b) Two driver-performance indexes of curvature were developed and were found to be significantly related to accidents on curves. Curves' perspective angle (as viewed by the driver correlated highly with accidents (r=0.51) but drivers are relatively insensitive to this information. Eye-movement patterns showed that drivers tend to successively fixate the edge-line of the curve before entering it, indicating that drivers perceptually negotiate the curve several seconds before entering it.