The Relative Importance of Pictorial and Nonpictorial Distance Cues for Driver Vision

There is evidence that nonpictorial distance cues, including accommodation and binocular disparity, play at most a minor role in driving relative to pictorial cues, such as relative size and linear perspective. However, the possibility that nonpictorial cues play a nontrivial role in at least some driving situations is of interest because of current and proposed applications of camerabased displays in driving. Such applications include the use of video systems as replacements for rearview mirrors and to enhance forward vision at night. By their nature, camera-based displays selectively eliminate or distort nonpictorial distance cues. This paper reviews analytical and experimental approaches for determining the relative importance of pictorial and nonpictorial cues in driving, and discusses the implications for the use of camera-based displays, as well as nonplanar rearview mirrors.