Driver Perception of Roadway, Traffic and Environment: A Basic Human Factor to be Considered in Road Design Standards.

More than 40 thousand people are killed and more than 3 million injured each year in road traffic accidents in both the United States and the European Union. In Europe 99 percent of fatal transportation accidents are road traffic related. More than 50 percent of all road crashes are attributed at least partly to late or missed perception of relevant information to avoid the accident. Safe driving requires adequate and efficient information gathering and processing from relevant sources within the road environment. A continuous input, in particular visual input, is essential for the orientation on the road. Orientation starts with the development of an internal representation of the road and ends with safe guidance and control of the vehicle. Perception is thereby the most important single basis for the drivers' decision making. Without knowledge about the actual traffic situation, organisation of appropriate and safe driving behaviour is not possible. Therefore, perception is a key issue in maintaining a high level of road safety. The design of a road should be in accordance to the perceptual capabilities of the driver. Changes in the design must be recognizable by the driver and transitions must be long enough to react appropriately. An extensive worldwide review of road design guidelines revealed that in most guidelines perception is underrepresented. The question of relevant information for driving tasks, optical guidance, perceptual illusions, reaction to combined signals as well as perception at night and under poor vision conditions are not adequately considered in the reviewed guidelines. Moreover, perceived road features may mislead drivers into making wrong decisions. Is it possible to construct roads in such a way that they are self-explaining in the sense that design features guide drivers to safe behaviour without further signs and signalling? This paper proposes recommendations with respect to perception for the consideration of human factors in the design of roads. Design recommendations were developed from the analysis of these factors which will be explained using an example. A methodology for integrating human factors into actual road design standards will be provided. For the covering abstract see ITRD E135448.