| Popis: |
With respect to traffic, roadworks are to an ever increasing extent performed during the dark hours. In these cases, lighting is a critical factor to consider. It is important that the road-user experiences good visual guidance past the road work area and that he or she is not bothered by glare from road work lighting, reflections in the roadway and other things. The safety and road work lighting should at the same time be good for the roadworker. This report reports on a pre-study of the joint Nordic project Störande ljus vid vägarbeten om natten (Disturbing lights during roadworks at night). The purpose of the project is to improve the safety both for road-users passing a roadwork area in the dark and for the persons working at the roadwork area. This particularly applies to night-time roadworks on major roads. In the main project, the disturbance that the different elements - flashing lights, vehicle lighting, electric fittings, reflections, etc. - cause the driver passing the roadwork area will be investigated, both separately and combined with each other. The project should lead to proposals for improvement and co-ordination of current regulations in the Nordic countries. Reflections in the roadway, especially when the roads are wet, can be experienced as problematic for the road-users. If the road surface is damp, glare occurs, for example from oncoming vehicle headlights or from flashing lights and signs by the road work area. In this pre-study, an investigation of the specular reflection in some typical Nordic road surfaces has been made, aimed to form the basis for planning the main study. The purpose with the pre-study has principally been to survey what values of specular reflection, retroreflection and luminance coefficient are common for road surfaces in the Scandinavian countries Denmark, Norway and Sweden. Finland, which originally should also have been part of the study, has been excluded due to resource and time limits, for the present. Measurement of the specular reflection has been made on dry and wet road surfaces with a modified retroreflectometer (of the type LTL-X). It has been supplemented with a vertical mirror directing the observation direction towards the lighting direction in such a way as to correspond to a motorist observing a point on the road surface 30 metres in front of the vehicle, which is lightened by a headlight 30 metres further away. Since the instrument was relatively untested, the aim of this pre-study was also to acquire experience and routines for measuring specular reflection. |
