This study aimed to investigate the relationship between age, gender, and risky behaviors of motorcyclists and their involvement in accidents. The results of a self-reported survey on motorcyclist behavior in the Taipei metropolitan area were analyzed. A two-step cluster analysis was used to classify motorcyclist behavior to different levels of risk within each of three risky behavior types. This was used to examine the regression relationship with accident risk. The results indicated that young and male riders were more likely to disobey traffic regulations, and that young riders also had a higher tendency towards negligence of potential risk and motorcycle safety checks. These "error" and "violation" behaviors increased the likelihood of an accident. However, in addition to these risks, there are additional factors that put young riders, particularly young female riders with the least riding experience, at increased risk of having an accident. These additional factors may be poor driving skills and less experience, all of which may result from the slack motorcycle licensing system. There should be increased emphasis on the necessity of providing appropriate training and a lower risk environment for novice riders., (c) 2006 Published by Elsevier Ltd.