Abstract
A study of three sites in Christchurch City, New Zealand, was used to identify the impacts that operating speed cameras have on speed. Speed cameras are found to reduce mean speed by about 2.2 kilometres per hour, and in one case they had a beneficial impact on speed distribution. Situational factors played important roles in the effects of speed cameras. Factors that affected camera effectiveness were wet roads, poor visibility and the presence of following vehicles. (a).