Warning Signal Design: A Key Human Factors Issue in an In-Vehicle Front-To-Rear-End Collision Warning System

Warning signal effectiveness issues associated with the design of a front-to-rear-end collision warning system are discussed. Potential negative effects are that warnings may occur rarely, startling the driver and adding to cognitive load and stress, or alternatively, warnings may occur frequently and be ignored by the driver. To minimize negative effects, four design concepts are considered: (a) a graded sequence of warnings, from mild to severe, (b) a parallel change in modality, from visual to auditory, (c) individualization of warnings, and (d) a headway – distance to lead car – display.