Development and analysis of road lighting : road surfaces and mesopic dimensioning

摘要

This work starts with a short introduction in which the energy consumption, proportion of different types of light sources, and procedures that have been introduced concerning energy saving in outdoor lighting are overviewed. It is followed by a historical review and research related to aspects of the topic referred to in this work: the luminance method used for photometric dimensioning of road lighting, road surface classification practises, and mesopic photometry. The work continues with a study of road surface reflection characteristics. Road surface reflection measurements were made to study the current state of the pavement materials used on Finnish roads. Pavement samples were extracted from roads and the reflection tables of the pavement samples were measured. The pavement materials used in Finland are somewhat dark and diffuse and the standard reflection tables give an adequate fit for the degree of specularity but not for the degree of lightness. The spectral reflection properties of various types and differently coloured pavement samples were studied. The results indicate that light sources that have a higher spectral light output in the longer wavelength region, such as high pressure sodium lamps, are more energy-efficient in terms of light reflected from the pavements compared to the ones with a high output in the short wavelength region. In addition, pavement materials made out of recycled materials and local limestone were studied. Light pavement materials reflect more light than darker pavement materials, and energy could be saved by increasing the spacing of the poles for the luminaires or reducing the power consumption of the luminaires. The work continues with a study of mesopic dimensioning in road lighting. The luminous efficacy of various types of luminaires and the use of mesopic dimensioning in road lighting design were studied. The study is followed by a case study where high pressure sodium lamp street lighting was changed to LED street lighting. The energy consumption of the installation was calculated and mesopic dimensioning was used. The results show that energy savings are possible when mesopic dimensioning is used by reducing the power consumption of the luminaire or by increasing the spacing of the poles for the luminaires. The work continues by studying the differences in using the standard r-tables and the measured r-tables of the pavement used in the road lightning design on Finnish roads. It was found that the R2 table should be used for road lighting design if the reflection property of the pavement is not known. The work is followed by a study of the use of light pavement materials and mesopic dimensioning. In this case the benefits of mesopic dimensioning are negligible when light pavement materials are used.