Visibility

An important reason for driving errors on two-lane rural roads is the misjudgment of road users concerning the real course of the road. This misjudgment has negative effects on the driver's behavior and to the road safety and results from the overlapping of elements of the horizontal and vertical alignment which can be due to an unfavorable spatial road alignment. Many of the problems that can be detected at the road infrastructure on two-lane rural roads are related to unfavorable conditions of visibility. Inadequate sight distance in only one aspect; partial road disappearance, sight distortion and insufficient recognizability of curves ahead are also important aspects. The hazard of these situations in the road network is raised by the eventuality that they lead the driver to misinterpretations. Insufficient visibility conditions are mostly affected by an unfavorable superposition of horizontal and vertical alignment. Up to now a design engineer couldn't identify the consequences of the spatial alignment, not even by computer-aided alignment. Now, with the assistance of newly developed software by the Universitaet Karlsruhe, perspectives from the driver's viewpoint along a road can be calculated, evaluated automatically according to quantitative visibility criteria and represented in a compact scheme, permitting the design engineer to Immediateely detect insufficiencies in visibility. As main quantitative criteria to detect safety relevant problems in spatial alignment, the depth of partial road disappearance along the driver's view has been developed. This new system is very important in practice and will assist in evaluating spatial road alignment quantitatively and in optimizing the road alignment from the user's viewpoint. Furthermore, in the future this system will be used as test software for road safety audits and for the safety judgment of existing unsafe roads (road sections with an accumulation of accidents).

< Back