ACCIDENTS INVOLVING LORRIES

115 road accidents were documented, reconstructed and analysed after investigations on site. In carrying these out observation was made of the point of impact, collision speeds, deformation of the interior of the vehicle and the mass ratio of the vehicles concerned. For car occupants there was a close relationship between the degree of severity of their injuries and the extent of the passenger cell deformation. Lorries exhibited substantial vehicle deformation only when in collision with vehicles of similar weight. Only in such cases were injuries found which were similar in severity to those suffered by car occupants. In the case of lorry/car accidents the severity of injuries to the lorry occupants were found to be relative to the lorry speed from 30 km/hr. The severity of injuries to car occupants was influenced not only by the collision speed of the lorry but also by the car's speed. The cause of this is related to the incompatible construction elements of the two vehicles (particularly differences in height between bumpers, deficient energy absorption in the construction of the lorry chassis and the hazardous external surface of the lorry with protruding components). A completely fundamental factor, however, is the unequal mass relationship which in every case caused greater deformation to the smaller partner in the collision. Measures suggested previously for improvements to the fronts of lorries, the mounting of protective units along the sides, and the introduction of an effective barrier to cars passing under the rear of a lorry all represent a valuable contribution towards reducing accident potential. (TRRL)