Abstract
In this field study a number of hypotheses are tested concerning the effective visual cues used by drivers in controlling their position on a straight road. The rationale of the experiment is that a particular cue is effective, when manipulation of its availability or strength has considerable effects on actual driving behavior. The results confirm the hypotheses about the optical effects of lateral position, lateral speed and heading rate as the effective perceptual cues in straight road driving. A specific difference between experienced and inexperienced drivers was found, suggesting that use of the optical cue related to lateral speed is only gradually learned.