The aim of this study was to investigate car driving skills and cognitive abilities after the consumption of methamphetamine and MDMA. In previous studies we have demonstrated significant decrements following sedative drugs such as cannabis, and stimulants such as dexamphetamine. We have also documented the presence of stimulant drugs in many fatal traffic accidents, especially those involving road-train truck drivers in Australia. There is however disagreement over whether acute doses of MDMA will impair or improve cognitive function and driving behaviours in humans. Ramaekers et al. [3] reported that an acute dose of 75mg MDMA improved tracking accuracy, but impaired speed adaptation during carfollowing. Dastrup et al. noted that abstinent Ecstasy users were not impaired on car driving skills, but did assume extra risk. In an analysis of traffic accidents involving stimulant drugs, Verschraagen et al. reported more fatalities involving MDMA than amphetamine.