Means of roadway delineation, such as pavement markings, post delineatiors, and Chevron signs, serve to provide the information during nighttime driving to maintain the correct lateral position of a vehicle on the driveway and to preview curves. In order to achieve that they have to be visible from a specific distance. This investigation is concerned with two issues dealing with the visibilty of road delineators, showing how it is possible, based on photometric and psychophysical data, to make quantitative predictions in those situations. The first issue deals with the optimal distance between post delineators which is computed from the candle power pattern of the headlights, the geometrical relations in the environment, and the contrast thresholds of the human observer. The second issue deals with the effect of width of line markings on their visibility.
Abstract