The effect on accidents of technical inspections of heavy vehicles in Norway

This paper presents a study of the effects on accidents of technical inspections of heavy vehicles (trucks and buses) in Norway. Multiple regression analysis is applied in order to estimate the effects of technical inspections, controlling for annual trend in accident rate, the number of new drivers and annual economic growth. It is found that abolishing inspections may result in an increase of 5–10% in the number of heavy vehicles involved in injury accidents; increasing the number of inspections by 100% is associated with a similar reduction in the number of accidents. These results are not statistically significant and highly uncertain. The study clearly illustrates many of the difficulties often encountered in non-experimental accident research.