Road Lighting Wout van Bommel Road Lighting Fundamentals, Technology and Application 2123 Wout van Bommel Lighting Consultant Nuenen The Netherlands ISBN 978-3-319-11465-1 ISBN 978-3-319-11466-8 (eBook) DOI 10.1007/978-3-319-11466-8 Springer Cham Heidelberg New York Dordrecht London Library of Congress Control Number: 2014956928 © Springer International Publishing Switzerland 2015 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. 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While the advice and information in this book are believed to be true and accurate at the date of publication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein. Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com) Dedicated to: the many students and attendees of conferences who, through their critical questions and participation in discussions, helped me over a period of some 40 years in learning how to explain lighting. Preface This is my second book on the subject of road lighting. The first, also titled “Road Lighting”, appeared in 1980 in the series “Philips Technical Library” published by Kluwer, with co-author Prof. J.B. de Boer. Since that time, the technology of road lighting has progressed to keep up with the changes in lamp and lighting technology, in traffic and automobile technology, and especially in the thinking about energy and the environment. The introduction of solid-state light sources (LEDs) has provided the possibility to design innovative, truly-sustainable lighting installations that are adaptable to changing circumstances such as traffic density and weather conditions. To avoid pitfalls when designing such installations, a detailed knowledge of the typical characteristics of the many different light sources, and especially also of all the aspects determining the final quality of road lighting, is essential. Completely-new fundamental research on vision and new application research on visual performance and comfort, conducted at many different research institutions at many different places all over the world, is now available as a basis for the specification and the design of effective, energy-friendly and sustainable road-lighting installations. The purpose of this present book, which represents a completely-fresh approach to the subject, is to outline the underlying principles on which modern road lighting is based and to leave the reader with an understanding of the background to the subject and a knowledge of how these principles should be applied in practice. The book is divided into three parts. Part One discusses the lighting of open roads for motorised traffic as well as for cyclists, pedestrians and residents. The first chap- ters deal with the purpose of road lighting, visual performance, including the effects of mesopic vision and of the aging eye, and visual comfort. Traffic safety, personal security and pleasantness are the main issues here. Following chapters describe the relevant lighting criteria for good and efficient road lighting and show and discuss the international, European and North American standards and recommendations for road lighting. Next, lamps and luminaires are reviewed in terms of their prac- tical properties and features, the intention being to facilitate a proper selection of this equipment for the various application fields. The road surface, as a means to reflect light towards the road user, must in fact be seen as part of the equipment of a road-lighting installation. Road-surface reflection properties are therefore dealt with in one of the “Equipment” chapters. The chapter “Design Aspects” provides the vii viii Preface link between theory and practice and supplies the reader with the knowledge needed for effective lighting design. The sustainability aspects of road lighting that have to be taken into consideration by the lighting manufacturer as well as by the lighting designer are also discussed in this chapter. The last chapter of part one deals with road-lighting calculations and measurements. Part Two of the book is devoted entirely to the subject of light pollution. Lighting that lights not only the area intended but that spreads out uncontrolled into the surrounding areas and into the sky is an annoyance to society. The disturbing effects to residents, to motorised and slow-moving traffic, to astronomers and to wildlife and natural vegetation are described. The zoning and curfewing tactics that are employed to restrict light pollution are explained, and lighting criteria that can be used by the lighting specifier and the lighting designer to guarantee that installations will stay within acceptable light pollution limits are defined. International, European and North American standards and recommendations on the restriction of light pollution are listed and discussed. The last Chapter of this Part 2 deals with that lighting equipment that is specifically suitable to limit light pollution. It also provides practical design guidelines on controlling light pollution. The subject of the third and final part of the book is tunnel and underpass lighting. The structure of this part is largely the same as that of part One. It has chapters discussing the purpose, the visual-performance fundamentals, the lighting criteria and the standards and recommendations for tunnel lighting. The concluding chapter deals with tunnel-lighting equipment and tunnel-lighting design aspects. This book is not aimed solely at the road-lighting designer and road-lighting en- gineer in municipalities and local governments or the student of lighting design and engineering; there is much of interest here too for the town planner, town traffic en- gineer and environmental specialist, as well as for the lamp and luminaire developers and manufacturers. I am much indebted to Derek Parker who did a great job editing this book, just as he did for the previous Road Lighting book, back in 1980. Contents Part I Road Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 Purpose and Benefits of Road Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . 3 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2 Basic Lighting Quantities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.1 Road-Surface Luminance for Motorized Traffic . . . . . . . . . . . . . . . 7 2.2 Illuminance for Pedestrians, Cyclists and Residents . . . . . . . . . . . . 8 2.2.1 Horizontal and Hemi-spherical Illuminance . . . . . . . . . . . 9 2.2.2 Vertical and Semi-cylindrical Illuminance . . . . . . . . . . . . . 10 Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3 Visual Performance for Motorists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.1 Object Contrast . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.1.1 Contrast and Contrast Threshold . . . . . . . . . . . . . . . . . . . . 11 3.1.1.1 Field Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.1.1.2 Contrast Polarity . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.1.1.3 Adaptation Luminance Under Non-uniform Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 3.1.1.4 Background Luminance Under Non-uniform Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 3.1.1.5 Object Shape . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 3.1.2 Silhouette Principle of Road Lighting . . . . . . . . . . . . . . . . 16 3.1.3 Contrast and Glare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 3.1.3.1 Disability Glare . . . . . . . . . . . . . . . . . . . . . . . . . 18 3.1.3.2 Spectrum and Disability Glare . . . . . . . . . . . . . 21 3.1.3.3 LEDs and Disability Glare . . . . . . . . . . . . . . . . 21 3.1.4 Contrast and Vertical Illuminance . . . . . . . . . . . . . . . . . . . . 21 3.1.4.1 Vertical Illuminance and Glare Restriction . . . 21 3.1.4.2 Vertical Illuminance and Reflection from the Road Surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 ix x Contents 3.2 Threshold Visibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 3.2.1 Revealing Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 3.2.2 Total Revealing Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 3.3 Supra-Threshold Visibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 3.3.1 Visibility Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 3.3.2 Small-Target Visibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 3.3.3 Relative Visual Performance . . . . . . . . . . . . . . . . . . . . . . . . 30 3.4 Visibility on Road Surrounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 3.5 Traffic Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 3.6 Adverse Weather Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 3.6.1 Wet Weather . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 3.6.2 Snow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 3.6.3 Fog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 3.7 Fixed Road Lighting and Car Lights . . . . . . . . . . . . . . . . . . . . . . . . . 39 3.7.1 Visibility of Objects on the Road . . . . . . . . . . . . . . . . . . . . 39 3.7.2 Glare from Oncoming Cars . . . . . . . . . . . . . . . . . . . . . . . . . 40 3.8 Pedestrian Road Crossings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 3.9 Optic Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 3.10 Lighting, Brain Activity and Alertness . . . . . . . . . . . . . . . . . . . . . . . 45 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 4 Visual Comfort for Motorists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 4.1 Lighting Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 4.2 Uniformity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 4.2.1 Longitudinal Uniformity . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 4.2.2 Luminance Gradient . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 4.3 Glare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 4.3.1 Discomfort Glare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 4.3.2 Spectrum and Discomfort Glare . . . . . . . . . . . . . . . . . . . . . 54 4.3.3 Discomfort from Glare Variation . . . . . . . . . . . . . . . . . . . . 55 4.3.4 LEDs and Discomfort Glare . . . . . . . . . . . . . . . . . . . . . . . . 56 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 5 Visual Performance, Comfort and Pleasantness for Pedestrians, Cyclists and Residents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 5.1 Visual Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 5.1.1 Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 5.1.2 Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 5.1.3 Visual Orientation and Guidance . . . . . . . . . . . . . . . . . . . . 64 5.2 Visual Comfort and Pleasantness . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 5.2.1 Spatial Brightness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 5.2.2 Colour Quality of Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 5.2.3 Discomfort Glare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 5.2.4 Impact During Daytime . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 Contents xi 5.3 Lighting Level, Uniformity and Glare Restriction . . . . . . . . . . . . . . 68 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 6 Mesopic Vision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 6.1 Spectral Eye Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 6.2 On-Line and Off-Line Vision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 6.3 S/P Ratio of Light Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 6.4 Adaptation Luminance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 6.5 Correction Factors for Photometric Quantities . . . . . . . . . . . . . . . . . 77 6.5.1 Peripheral Task Performance . . . . . . . . . . . . . . . . . . . . . . . . 77 6.5.1.1 CIE Correction Factors . . . . . . . . . . . . . . . . . . . 77 6.5.1.2 Consequences for Road Lighting Practice . . . . 79 6.5.2 Brightness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 6.5.2.1 Models for Brightness Prediction . . . . . . . . . . . 80 6.5.2.2 Consequences for Road Lighting Practice . . . . 80 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 7 Age Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 7.1 Age and the Visual Mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 7.2 Age and Visual Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 8 Lighting Quality Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 8.1 Motorized Traffic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 8.1.1 Lighting Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 8.1.2 Uniformity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 8.1.3 Lighting of the Surrounds . . . . . . . . . . . . . . . . . . . . . . . . . . 91 8.1.4 Glare Restriction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 8.1.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 8.2 Pedestrians, Cyclists and Residents . . . . . . . . . . . . . . . . . . . . . . . . . . 93 8.2.1 Lighting Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 8.2.2 Uniformity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 8.2.3 Lighting of the Surrounds . . . . . . . . . . . . . . . . . . . . . . . . . . 94 8.2.4 Glare Restriction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 8.2.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 8.3 Spectrum of Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 9 Standards and Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 9.1 CIE Recommendation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 9.1.1 Lighting of Motorized-Traffic Routes . . . . . . . . . . . . . . . . 98 9.1.2 Lighting of Conflict Areas . . . . . . . . . . . . . . . . . . . . . . . . . . 99 9.1.3 Lighting for Pedestrians and Low-Speed Traffic . . . . . . . . 99 9.1.4 Spectrum of Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 9.1.5 Adaptive Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102