The purpose of this study is to propose an extended model of planned behaviour (TPB) to understand better the link between motorcyclists' type of vehicle and their intention to exceed the speed limit on a 90 km/h road. 257 riders of sport and touring vehicles answered a questionnaire put on line on the web site of a national organization. In line with our hypothesis, findings show that taking into account the different categories of motorcyclists is highly relevant; attitude and group norm appear for each category of motorcyclists. Concerning the sport riders, except attitude and group norms, de-restriction explains the intention to exceed the speed limit. For touring riders, except attitude and group norm, sensation seeking appears to be a predictive factor that is distinctive from the other categories. This study highlights the necessity to focus on motorcyclists according to the type of vehicles they ride rather than considering motorcyclists as a homogeneous population. The predictive factors of exceeding the speed limit are different from one type of motorcyclist to another. Studies examining the predictive factors of risky habits usually consider a single category of motorcyclists only; in contrast, our investigation distinguished between different categories of motorcyclists, and our results invite concerned parties to adapt their awareness-raising actions to the characteristic features of these categories.