A simulator is described that can be used to investigate a variety of perceptual factors cencerned with driving. It employs a back projection system for presenting a driver's eye view film, in colour, to subjects sitting in a modified car body. The impression of being in a real moving car is increased by providing suitable auditory and vibratory inputs. Studies designed to validate the use of the simulator as an acceptable research tool are described. It was demonstrated that similar results were obtained in an experiment requiring assessments of risks, irrespective of whether subjects made their ratings while driving around a test route in their cars or while viewing a film of the route while in the simulator. It was also shown that emotional responses to traffic events in the simulator obtained by measuringf skin conductance changes, were typical of those found in the road situation. The results of a questionnaire completed by the drivers revealed that the simulator provides an acceptably realistic simulation of the driver's perceptual environment. Possible improvements are discussed and finally a variety of potential uses of the simulator, as a research tool, are given.