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Michael A good summary site on relevant studies and arguments to 1994 is http://www.ibiblio.org/rdu/DRLs/studies.htm There was a recent study reported - details below Effects of daytime running lights on multiple-vehicle daylight crashes in the United States. Farmer CM, Williams AF. Accid Anal Prev 2002; 34(2): 197-203 Where a 3.2% decrease in multiple vehicle accidents was determined for the vehicles with DRL's versus those without DRL's And there was a study that looked at light levels and various crashes" The role of ambient light level in fatal crashes: inferences from daylight saving time transitions. Sullivan JM, Flannagan MJ. Accid Anal Prev 2002; 34(4): 487-498. Correspondence: John M. Sullivan, University of Michigan Transportation Research Institute, Ann Arbor 48109-2150, USA; (email: [log in to unmask]). It showed the major impact was on pedestrian crashes. This would suggest that DRL's may be most effective in preventing this type of crash. However the two most important things to keep in mind that the basic issue is conspicuity as related to the contrast of the lights or vehicle with its background, and that conspicuity does not necessarily require high light output as during the day the lights are not being used to light up the road ahead and it is only conspicuity for a range of say 100 metres that is the issue. And another issue related to the colout temperature of the lights relevant to the back ground - if there is Australian summer blue sky behind the vehicle then the contrast may be low for instance - vehicle coming over a crest. Hence there is the potential to produce high conspicuity/contrast light emitting devices that do not require high wattages. And these would have the additional benefit of glare not interfering with oncoming drivers . There is further potential to electronically adjust the output of DRL's to be low in low level light situations and high at the middle of the day to further reduce power consumption. For the average car in Australia travelling 18000 km per year at an average of say 50 km/he, and using two 55w headlamps as the illumination mechanism, having DRL's on 50% of the time, and an engine efficiency of 25% and an alternator efficiency of 70%, the extra fuel consumption is about 10 litres which at a cost of $0.90 per litre creates an annual cost of around $9.00. For all vehicles in Australia this will equal about $100 M per year. In contrast reducing the power required by 90% would reduce this to $10 M per year Suggest that in addition to searching out papers on DRL's that you talk to lighting/conspicuity consultants like Kevin Poulton 03 9807 4502 who is very critical of a lot of the "lighting" related Australian and ISO standards because they prescribe light levels for street lighting for instance not levels of conspicuity/contrast (You will all have experiences yellow sodium lights and been aware that they provide poor contrast and so are less safe that white light). regards John Lambert MIEAust, CPEng 180 785 Bachelor of Engineering (University of Melbourne), ARMIT (Mechanical) Director and Company Secretary John Lambert & Associates Pty Ltd ACN 090 833 873 ABN 59 090 833 873 235 Wandana Drive, Wandana Heights, Victoria, 3216 Australia Phone: [61 3] 5249 1228 Fax: [61 3] 5249 1146 Mobile or cell phone: 0417 033 258 Email: [log in to unmask]