An awareness of the existence of the phenomenon of lateral displacement has been extant for many years and much descriptive information has been published on this driving phenomenon. However, the study reported here constitutes what is believed to be a first attempt to determine the process drivers use to locate objects and to define the factors that cause a driver to displace laterally. The results obtained in a controlled study on a test track showed that drivers locate an object they are overtaking on the basis of the angular velocity of the object. If a driver can detect this lateral movement, he knows that the object cannot be in his path. If there is no much velocity, the object is perceived as an obstruction and the driver must displace. The results also provide a basis for predicting the effects of lateral displacements on lane width, size of objects near the path of travel - fixed or moving - and the speed of the vehicle. Findings reported here have many implications related to highway transportation and can provide some criteria for design, speed controls, and roadside developments in plans for future highways and improvement of existing ones.
Abstract