Samenvatting
On can schematically confront the motor cyclist whose forehead strikes the adverse vehicle or the fixed obstacle with death often occurring immediately, with the moped rider, when struck laterally, who almost invariably suffers temporal impact with death usually being delayed. The authors consider the most important facts to be the variable frequency of impacts between the head and an adverse vehicle and the high rate of temporal impacts which justify the developments of helmets providing an effective protection for this zone.