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]