Safety relevance of vision research and theory.

This article discusses the importance of drivers' visual perception to road safety. Evidence is provided to show that the visual perception of a person who is moving at high speed can be seriously affected by both poor visibility and defective eyesight. The point is made that the human eye and mind can adapt well to one adverse condition such as heavy rainfall or even one visual defect, but not to multiple problems. Research must therefore be conducted under real traffic conditions rather than under ideal conditions, where perhaps only one variable is studied. Papers published in the last 3 'Vision in Vehicles' conferences are analyzed to investigate how many studies have actually been done on the effect upon perception of multiple factors. Suggestions are made about future research requirements.