A research titled ‘Driver age and vehicle engine size effects on fault and severity in young motorcyclists accidents’ co-authored by G.Yannis, J.Gollias and E.Papadimitriou from NTUA, was published in the Journal Accident Analysis and Prevention in November 2004. Data from the national accident database of Greece were used to calculate accident severity and relative fault risk rates. Accident severity modelling revealed a significant second-order interaction between severity, driver age and two-wheel engine size. On the contrary, no second-order effects were identified in fault risk modelling. Moreover, a significant effect of driver age on accident fault risk was identified. The effect of engine size was not significant.