Current levels of service for delineation are provided in a methods based approach which defines the device or devices to be used and a level of maintenance to be applied. Quality or level of performance is often not addressed directly, but rather only by implication. This approach, while reasonable, is not linked in a transparent way to a sound theoretical basis of the service being provided and how this service increases with incremental improvements. This paper recommends preview time as a measure of the level of service. Preview time is a measure of the driving time ahead that the marking is easily visible. Preview time is influenced by the driver's age, vehicle type, speed, other vehicles, the road surface and lighting and weather conditions. Computer models are available for calculating preview time and relating it to quantifiable properties of the marking. By using preview time as a measure of the level of service, the percentage of the driving population, and the range of driving conditions being catered for is better identified. Linkages to benefits is also more explicit. (a)
Abstract