The doctoral dissertations of the former Helsinki University of Technology (TKK) and Aalto University Schools of Technology (CHEM, ELEC, ENG, SCI) published in electronic format are available in the electronic publications archive of Aalto University - Aaltodoc.
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Doctoral dissertation for the degree of Doctor of Science in Technology to be presented with due permission of the Faculty of Electronics, Communications and Automation for public examination and debate in Auditorium S4 at the Aalto University School of Science and Technology (Espoo, Finland) on the 4th of June 2010 at 12 noon.
Overview in PDF format (ISBN 978-952-60-3083-8) [1175 KB]
Dissertation is also available in print (ISBN 978-952-60-3082-1)
The work starts with a short introduction concerning the history of road lighting, outlining the trends and changes that have taken place in road lighting research during the past century. The introduction is followed by a review of trends, directions, and problems in current road lighting research and practice. The following part of the work introduces an advanced approach to road lighting measurements and calculations, based on the use of an imaging luminance photometer and the Road LumiMeter v2.0 computer program. The work sets out to investigate the variations in the characteristics of the quality of the road lighting at the same pilot locations in relation to the calculation methods used. In the work mesopic visual performance and the effects of the spectral transmittance of the vehicle windshield on the visibility conditions of the driver are also analysed.
The work continues with road lighting measurements in various weather conditions in order to study the effects of snowy and wet road surface conditions on road lighting luminances. The results show that in Finland, snowy conditions offer very good opportunities to save electricity without adversely affecting either the safety of driving or the quality of road lighting. The following measurements set out to investigate the contribution of halogen and high-intensity discharge headlights to road lighting and whether this has a conflicting effect on the luminance contrasts of various targets located on the road or at the side of the road. The results indicate that, in general, the use of vehicle headlights in the presence of road lighting reduces the luminance contrasts of targets.
The work continues with road lighting visibility experiments which study the visibility of achromatic and coloured targets in MH lamp and HPS lamp installations. The results show that colours have a major effect on target visibility if the road is illuminated with a light source with adequate colour rendering properties. Finally, pavement sample measurements are made to study the effects of aggregate lightness and aggregate colour on the reflectance properties of pavements. HPS lamps are found to be more effective than MH lamps in terms of light reflected from pavements.
This thesis consists of an overview and of the following 8 publications:
Keywords: road lighting, measurements, calculations, imaging luminance photometer, weather conditions, vehicle headlights, colour contrast, pavement materials
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© 2010 Aalto University School of Science and Technology