A Field Test of Police Vehicle Presence on Speed(ing): Parked, Unoccupied, and Effective

As part of the present research, we employed a field study paradigm to test the effects of an unoccupied police vehicle on speed(ing) along a voluminous highway offramp in Western Canada. During the intervention period, a randomly assigned, marked police vehicle was parked nightly at the target location while radar-recording devices captured the speed of passing vehicles. Our analyses of speed data collected before, during, and after the intervention period, both before and at the target location, indicated that the average speed of vehicles and the proportion of speeding vehicles were significantly lower in the presence of the unoccupied police vehicle. We discuss the results of our police-directed field study with respect to theory, research, and practice.