And for those who are not trying to have an accident...
"Extensive studies into the effect of daytime running lights on the car accident rate of an individual car show that the use of headlamps reduces crashes by around 15%."
"If we look at these studies in a little more detail, the mean results show that daytime running lights reduce front or side-on collisions by 13% and rear-end collisions by 16%. Furthermore, the number of pedestrian collisions was reduced by 25%; a massive reduction in a type of collision which often results in serious personal injury."
http://www.youclaim.co.uk/car/car-accident-reduction-and-drl.htm
Just google it! If you really want to read more about it...
http://www.ibiblio.org/rdu/DRLs/studies.htm
U.S. Department of Health and Human Services, Public Health Reports , Vol. 110 ; No. 3 ; Pg. 233; ISSN: 0033-3549 (May, 1995).
In summary, although the studies of DRLs have differed in design, analysis techniques, and outcome measures, the later studies are largely in accordance with the earlier ones, indicating that the overall effect of DRLs on motor vehicle crashes is positive.