the wearing of high visibility yellow, orange or bright red jackets. MAIDS report The most recent large-scale study of motorcycle accidents is the MAIDS report carried out in five European countries in 1999 to 2000, using the rigorous OECD standards, including a statistically significant sample size of over 900 crash incidents and over 900 control cases. The MAIDS report tends to support most of the Hurt Report findings, for example that "69% of the OV [other vehicle] drivers attempted no collision avoidance manoeuvre," suggesting they did not see the motorcycle. And further that, "the largest number of PTW [powered two-wheeler] accidents is due to a perception failure on the part of the OV driver or the PTW rider." And "The data indicates that in 68.7% of all cases, the helmet was capable of preventing or reducing the head injury sustained by the rider (i.e., 33.2% + 35.5%). In 3.6% of all cases, the helmet was found to have no effect upon head injury" and "There were no reported cases in which the helmet was identified as the contact code for a serious or maximum neck injury." Olson Report A lesser-known study, known as the Olson Report after the lead investigator in a 1979 University of Michigan study, found that rider safety could be enhanced by wearing conspicuous clothing (especially yellow-green); using headlights in daytime, especially modulated headlights; and using running lights and wearing retro-reflective clothing at night. Inconclusive findings on conspicuity A New Zealand study using data taken between 1993–96 in the city of Auckland, a "predominantly urban area" (Wells et al. ) supported the Hurt Report's call for increased rider conspicuity, claiming that riders wearing white or light colored helmets, fluorescent or reflective clothing or using daytime headlights were under-represented when compared to a group of motorcycle accident victims. The accident victims were those who were killed, admitted or treated at hospital "with an injury severity score >5 within 24 hours of a motorcycle crash". Accidents that did not result in hospitalization or treatment for a critical injury, or a death, were not considered, nor was there any consideration of involvement of other road users, or culpability. The definition of reflective or fluorescent clothing was taken to include "clothing or other articles such as a jacket, vest, apron, sash, ankle or wrist band, or back pack including stripes, decals or strips". No assessment of the type (open or full-face)