Car driver behaviour during differing driving maneuvers.

Motorcycle-automobile accidents occur predominantly when the car driver turns left across the motorcyclist's right-of-way. Efforts to decrease this specific collision configuration, through increase in motorcycle conspicuity, have concentrated on the physical parameters of the motorcycle and its rider. The investigations reported here are directed toward the examination of car-driver behavior during the left-turn sequence. Two experiments are reported which used simultaneous video-taping of the driver themselves and the forward-looking display scene. In the first experiment, individuals followed a preset on-road course and were observed for workload responses such as probe-response time, subjective assessment, physiological activation, etc. Significant increases in workload during turn sequences compared to straight driving were noted. The second experiment included partial replication of previous performance assessment but examined principally driver eye movement and fixation, while isolating the separate effects of head movement. Subjects drove round a one square block course making repetitive left turns at intersections. One of the intersections was controlled by a traffic light and involved very heavy traffic, pedestrians, and other distractors. The other intersection was a two-way stop and involved light traffic flow. Descriptive data concerning behavior at these intersections is presented. Overall results indicate that turning maneuvers tax the information processing system more, result in higher workload and so increase the potential for detection failure. Such a propensity is increased by the higher structural interference that can be expected during turns. All left turns are not the same. The second experiment provides initial indications that eye/head behaviors are highly contingent upon the precise turn configuration. This argues that a taxonomy of left-turns is needed. Even with such differentiation, further understanding of the dynamics of driver behavior is required to increase recognition of on-coming motorcycles during this critical maneuver. (A) For the covering abstract of the conference, see IRRD 837684.