In Situ–Messungen von Reflexionseigenschaften von Fahrbahnoberflächen

Reflection properties are an important aspect in road surface characteristics. Characterisations deal almost always with public lighting and tunnel lighting. Reflective properties of road surfaces are almost only measured in laboratories. This research project investigates road reflection properties with regard to roadlighting, vehicle headlight as illuminator, Accessibility aspects, environmenmental impacts of outdoor lighting and daylight. As a result, a system of characteristic values is identified, covering all these aspects. To get this, reflection properties of 57 different road surfaces were measured in detail in the lighting lab. The sample included cement concrete pavements, asphaltic pavements and coatings with aggregates. Every surface was characterized by several luminance factors and more than 450 luminance coefficients. The relations between many of them where analysed. With portable devices, measurements were made on-site on 14 different road surfaces. The variation of the reflection properties across the road width was characterized for three characteristic values. These results were used to estimate the uncertainty of road reflection characterization by measured area and surface area to be characterized. In addition, two out of three characteristic values were measured with two different measurement methods each. The corresponding methods gave the same results. As a conclusion, road reflection properties can be characterized as a road surface characteristic by a manageable set of characteristic values with regard to all identified aspects. Most of them can be measured in laboratory and in situ. Another conclusion is that measurements in the laboratory and in situ partly allow different characterizations and have different limitations in detail. Research is recommended to address aspects of road reflection properties that can not be measured in situ. Some other work needs to be done to make equipment available commercially for in situ measurements and to ensure measurement qualitiy.