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Description: This investigation has compared the lighting performance of concrete and asphalt surfaces of parking lots. The value of Q0 (measure of total light reflected from a surface) was documented by analyzing the results of a large sample of road surfaces across North America. The spectral reflection characteristics of both surfaces have been measured and results indicate that concrete and asphalt tend to reflect shorter wavelengths less. Visibility Level (ability to detect targets such as wheel stops) was investigated and it is determined that the visibility level is dependent upon the reflectivity (r) of the target. The resulting amount of energy saved for a typical parking lot lighting system was attained for equivalent average surface luminances. equivalent average surfaces were compared in two ways: by modifying lamp power and by reducing the number of lighting poles. The amount of energy saved using concrete as a surface has been documented. Based on the results, it is recommended that concrete should be used as the surface for parking lots. This is due to the higher reflectance of concrete over asphalt surfaces since comparable luminance levels could be obtained with less energy than necessary for asphalt surfaces. Also, the iso-luminance diagrams for concrete parking lots are similar as indicated in Appendix 4. This implies that besides requiring less lighting, concrete based parking lots will also have a more uniform pavement luminance distribution, which is a desirable attribute. As for the choice of lamps, all other factors being equal, High Pressure Sodium would be more effective because it contains less blue (shorter wavelength) than for example Metal Halide Lamps. Blue is reflected lesser from both concrete and asphalt surfaces. This report is also found on DVD021.
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