Visual Grouping and Its Application to Road Design and Traffic Control

Visual or perceptual grouping refers to the tendency of the visual system to aggregate discrete stimuli into larger wholes. It is the process of determining which regions and parts of the visual scene belong together as parts of higher order perceptual units such as objects or patterns. The central hypothesis of Gestalt psychology is that the mind forms these global wholes through autonomous processes in the brain using the following principles - simplicity, proximity, similarity, closure, common fate, continuity, and figure-ground. An understanding of the Gestalt principles of visual grouping helps explain why alert and attentive motorists can sometimes make inexplicably bad decisions concerning speed and/or path of travel, and can be used by designers to engineer safer roads.