Functional Requirements for Daytime Running Lights
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UMTRI-2003-11 FUNCTIONAL REQUIREMENTS FOR DAYTIME RUNNING LIGHTS Kåre Rumar May 2003 FUNCTIONAL REQUIREMENTS FOR DAYTIME RUNNING LIGHTS Kåre Rumar The University of Michigan Transportation Research Institute Ann Arbor, Michigan 48109-2150 U.S.A. Report No. UMTRI-2003-11 May 2003 Technical Report Documentation Page 1. Report No. 2. Government Accession No. 3. Recipient’s Catalog No. UMTRI-2003-11 4. Title and Subtitle 5. Report Date May 2003 Functional Requirements for Daytime Running Lights 6. Performing Organization Code 302753 7. Author(s) 8. Performing Organization Report No. Rumar, K. UMTRI-2003-11 9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) The University of Michigan 11. Contract or Grant No. Transportation Research Institute 2901 Baxter Road Ann Arbor, Michigan 48109-2150 U.S.A. 12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered The University of Michigan Industry Affiliation Program for 14. Sponsoring Agency Code Human Factors in Transportation Safety 15. Supplementary Notes The Affiliation Program currently includes AGC America, Autoliv, Automotive Lighting, Avery Dennison, BMW, DaimlerChrysler, DBM Reflex, Denso, Exatec, Federal-Mogul, Fiat, Ford, GE, Gentex, General Motors, Guardian Industries, Guide Corporation, Hella, Honda, Ichikoh Industries, Koito Manufacturing, Labsphere division of X-Rite, Lang-Mekra North America, LumiLeds, Magna International, Mitsubishi Motors, Nichia America, North American Lighting, OSRAM Sylvania, Philips Lighting, PPG Industries, Reflec USA, Reflexite, Renault, Samlip, Schefenacker International, Sisecam, Solutia Performance Films, Stanley Electric, Toyota Technical Center U.S.A., Valeo, Vidrio Plano, Visteon, 3M Personal Safety Products, and 3M Traffic Control Materials. Information about the Affiliation Program is available at: http://www.umich.edu/~industry 16. Abstract Late detection is the basic mechanism responsible for daytime collisions. One goal of this report is to review evidence concerning the effectiveness of daytime running lights (DRLs) to increase vehicle conspicuity, and thereby facilitate vehicle detection and reduce the number of daytime collisions (including collisions between cars and unprotected road users). Another goal is to recommend lighting characteristics of dedicated DRLs. The available accident studies indicate that DRLs are effective in reducing the number of daytime collisions. Furthermore, this reduction is larger for pedestrians and cyclists than for motor vehicles. Evidence indicates that the minimum intensity of DRLs should be about 400 cd. Although increased intensity of DRLs results in increased effectiveness, it also results in increased glare. Consequently, an upper limit on the intensity of DRLs is justified. Arguments are presented that for the relevant levels of ambient illumination (1,500 – 40,000 lux), the maximum intensity for dedicated DRLs should be about 1,500 cd. The report also discusses recommended DRL light distributions, non-dedicated DRL alternatives, and the use of rear lamps with DRLs. 17. Key Words 18. Distribution Statement daytime running lights, DRLs, conspicuity, glare, daytime, review, Unlimited recommendations, regulations, pedestrians 19. Security Classification (of this report) 20. Security Classification (of this page) 21. No. of Pages 22. Price None None 62 i ACKNOWLEDGMENTS Appreciation is extended to the members of the University of Michigan Industry Affiliation Program for Human Factors in Transportation Safety for support of this research. The current members of the Program are: AGC America LumiLeds Autoliv Magna International Automotive Lighting Mitsubishi Motors Avery Dennison Nichia America BMW North American Lighting DaimlerChrysler OSRAM Sylvania DBM Reflex Philips Lighting Denso PPG Industries Exatec Reflec USA Federal-Mogul Reflexite Fiat Renault Ford Samlip GE Schefenacker International Gentex Sisecam General Motors Solutia Performance Films Guardian Industries Stanley Electric Guide Corporation Toyota Technical Center U.S.A. Hella Valeo Honda Vidrio Plano Ichikoh Industries Visteon Koito Manufacturing 3M Personal Safety Products Labsphere division of X-Rite 3M Traffic Control Materials Lang-Mekra North America ii CONTENTS ACKNOWLEDGEMENTS ........................................................................................... ii 1. EARLY EXPERIENCES ......................................................................................... 1 2. BASIC CONCEPT AND PERCEPTUAL THEORY ............................................. 3 3. DRL PURPOSE AND PROBLEM ANALYSIS ..................................................... 6 3.1. General conditions in which DRLs should work .............................................. 6 3.2. Potential advantages with DRLs other than enhanced conspicuity .................. 7 3.3. Potential risks following an introduction of DRLs ........................................... 8 4. METHODOLOGICAL PROBLEMS ...................................................................... 9 4.1. Perceptual studies .............................................................................................. 9 4.2. Accident, environmental and cost studies ......................................................... 10 4.3. Compensatory behavior .................................................................................... 11 5. GENERAL CONDITIONS ...................................................................................... 12 5.1. Ambient illumination level and latitude ............................................................ 12 5.2. Weather conditions ........................................................................................... 14 5.3. Urban/rural conditions ...................................................................................... 14 5.4. Pedestrians and cyclists ..................................................................................... 15 5.5. Legislation ......................................................................................................... 15 5.6. Public attitude ................................................................................................... 16 5.7. Exisiting regulations and requirements (standards) .......................................... 17 6. PERCEPTUAL AND TECHNICAL ISSUES ......................................................... 19 6.1. Novelty effect .................................................................................................... 19 6.2. Peripheral conspicuity ....................................................................................... 19 6.3. Central conspicuity ........................................................................................... 20 6.4. Distance estimation ........................................................................................... 21 6.5. Speed ................................................................................................................. 21 6.6. Position, identification and masking of other road users .................................. 22 6.7. Masking of signal lights .................................................................................... 23 6.8. Glare .................................................................................................................. 23 6.9. Non-optimal DRL alternatives .......................................................................... 24 iii 6.10. Effects on motorcycle conspicuity ................................................................ 24 6.11. Optimal lighting characteristics ..................................................................... 26 6.12. Light sources .................................................................................................. 28 6.13. Wiring and integration ................................................................................... 28 7. GENERAL EFFECTS OF DRLs ............................................................................. 30 7.1. Crash effects....................................................................................................... 30 7.2. Fuel consumption and wearing out of light sources ......................................... 32 7.3. Environmental effects ....................................................................................... 32 7.4. Benefit and cost studies .................................................................................... 33 8. STUDIES IN PROGRESS ....................................................................................... 34 9. CONSIDERATIONS ............................................................................................... 36 9.1. Positive effects .................................................................................................. 36 9.2. Negative effects ................................................................................................ 37 9.3. Unresolved questions ........................................................................................ 37 9.3.1. Lamp types acceptable as DRL .............................................................. 38 9.3.2. Requirements for dedicated DRLs ......................................................... 38 9.3.3. Other lights and DRLs ........................................................................... 44 10. RECOMMENDATIONS ......................................................................................... 46 11. REFERENCES ........................................................................................................