This report presents the results of a trial of the use of hidden speed cameras in rural (100kph) speed limit areas in the Midland Police region of New Zealand, conducted from July 1998 to June 1999. The objective of the trial was to test the effectiveness of using hidden cameras, compared with the extensive use of highly visible speed cameras in the rest of New Zealand during the trial period. The hidden cameras' effectiveness was measured by comparing the Midland Police region with the rest of New Zealand in terms of changes in speeds, crash and casualty rates, and public attitudes towards speeding and speed camera enforcement, which occurred during the period of hidden speed camera deployment and the preceding month of initial publicity about the trial. Compared with the rest of New Zealand, open road mean speeds fell by 3.2kph at speed camera sites and 1.6kph on all roads, and 85th percentile speeds fell by 3.0kph at speed camera sites and 4.0kph on all roads. During the trial period, it is estimated that, on open roads, the crash rate fell by 11% and the casualties fell by 19%, due to the hidden speed cameras and their associated publicity. There was also a growing acceptance by drivers in the trial area of the use of hidden speed cameras, and a recognition by them that they were speeding less.
Abstract