Automatic speed enforcement by means of photo radar was introduced in Norway in 1988. The results of a before-and-after study of the effects of automatic speed enforcement on accidents are reported in this paper. The study controlled for general trends in the number of accidents and regression to the mean. A statistically significant reduction of 20 percent in the number of injury accidents was found. The number of propertydamage-only accidents was reduced by 12 percent. The results of this study confirm the results of previous studies of the effects of automatic speed enforcement on accidents.