Cognitive Characteristic of Driver's Curve Detection in terms of Road Scene Factors

Abstract

In this study, the effects of road scenes and traffic control devices on a driver's curve detection performance were investigated. The field experiments were conducted on an 11 -km section of highway running through Shikotsu-Toya National Park in Hokkaido. The driver obtains directional information from the road scene ahead and from traffic control devices on the corner of the target curve. The characteristics of the road scene were determined subjectively. The configurations of traffic control devices at 21 curves were obtained from the road maintenance database and measured at site for each curve. Twenty-three subjects participated in the experiment. Each of the subjects drove an inst rumented vehicle and pressed a button as soon as she/he recognized the direction of the target curve. The detection distance of each curve was measured. The maximum detection distance (MDD) of each target curve was determined by the experimenter. A curve detection index (CDI), defined as (MDD-detection distance) divided by MDD, was employed in order to compare detection performance for each of 21 curves. The characteristics of detection performance for all of the 21 curves were determined by the cluster analysis and multiple regression analysis. The 21 curves were classified into 4 groups according to the results of cluster analysis. The results of multiple regression analysis revealed that the subject's driving in the daytime obtained directional information about the curve from the road scene, while their driving at night obtained directional information from traffic control devices such as guardrails, utility poles and chevron signs. The results of this study indicate that viewing cues should be considered when traffic control devices set up at the side of curve, and appropriate traffic control devices should be selected to enable safe detection of a curve. It should be noted, however, that further investigations in terms of cues and CDI are required for various curves and conditions.