A combined theoretical/experimental approach was taken in this research. A theory for delineation visibility and driver perceptual requirements was developed and tested in a laboratory simulation. Further validation tests were then conducted in an instrumented vehicle on the open highway. The simulation and field test results were compared and connected analytically through the use of the previously developed visibility theory, and a model was developed to quantify steering performance in terms of delineation contrast and configuration (i.e., line segment and gap lengths). It was found that the quality of delineation under adverse visibility conditions depends on a combination of contrast and configuration. Conclusions are drawn about delineation contrast and configuration requirements, and suggestions are made on practical field techniques for measuring delineation contrast.
Abstract