Studies on the suitability of various photometric parameters for assessing the brightness of paved road surfaces and development of a transportable device for measuring brightness in situ and in the laboratory
In addition to energy-efficient lighting technologies for luminaires, the choice of road surface strongly influences energy requirements for street lighting. For example, by using lighter rather than darker road pavements, energy consumption can be cut to one third while still ensuring comparable luminance levels in terms of traffic safety. Light-colored pavements also reduce the thermal load on road surfaces because they absorb less heat.
When it comes to designing artificial lighting systems and to quality assurance, up till now the reflective behavior of road pavements has invariably been determined by measuring core samples of the respective road or samples of new pavements in the laboratory. As far as cores are concerned, in addition to the time-consuming procedure to extract them, there is a risk that the samples taken may not be representative. For example, samples of new pavements are artificially abraded. This calls for a great deal of experience on the part of the person responsible for the measurement when making preparations for the test.
In a project funded by the German Federation of Industrial Research Associations AIF (Arbeitsgemeinschaft industrieller Forschungsvereinigungen “Otto von Guericke” e. V.) (Grant No. 15083 BG/2), various typical photometric indices were examined for their suitability for measuring the brightness of road surfaces. An innovative transportable device was also developed for measuring brightness in situ and in the laboratory.