An analysis of the circumstances preceding severe occupational injuries as a consequence of impacts has shown that well-known risks are of great importance in 75 per cent of the cases. This indicates that the subjective cause "neglect" is common. The negligence is distributed to the same extent among employers as among employees. Negligence by the employers was defined as obvious violations according to the Law of Workers’ Safety or Regulations issued by The National Board of Occupational Health and Safety. Negligence by employees was defined as actions against specific orders or common sense. As a result of this study additional research concerning the execution of Criminal Law in occupational accidents has been carried out. The law has also been changed regarding prosecution in cases of breaking the Law on the working environment.In situations where elimination of risks is not possible it is a most important task to minimize the risk of severe injury. In four of the studies there are examples of minimization of injuries by increased usage of personal safety equipment, improved rescue and by modifying the environment. If personal safety equipment could be used in all relevant situations the incidence of severe injuries at the place of work would decrease by more than 25 per cent. However, the crucial insufficiencies as to the specifications of personal protective equipment must be emphasized. This should stimulate the development of environmental changes, thus preventing the build-up and release of potentially dangerous energy. Working alone and late rescue for other reasons, together with other circumstances following the injury made the injuries worse in a little more than 10 per cent of the cases.In the studies concerning injuries as the result of impacts in trucks and buses it is shown that a lot of trucks turn over and that a large number of injuries occur as a result of deformation of the cabins. A safety belt would offer good protection against injury in about half of the cases. Safety in trucks and buses could be improved by the introduction of a deformative zone in front of the occupants. Front designs of cab-over vehicles should be changed and the use of seat belts in trucks and buses should be made compulsory. Passive seat belts, knee bars and air bags are interesting alternatives and additions to manual seat belts for commercial drivers. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1989, härtill 5 uppsatser</p> / digitalisering@umu