Speed Reduction Effects of Drone Radar in Rural Interstate Work Zones

Three experiments were conducted to evaluate the effectiveness of using drone (passive or unmanned) radar guns on vehicle speeds in construction zones. Experiment 1 was an exploratory study to find the immediate (less than an hour) effects of using one drone radar gun. Experiment 2 was conducted for a longer time period (a few hours) to evaluate the effects of using one drone radar gun. Experiment 3 evaluated the effects of using two drone radar guns and their lasting effects on vehicle speeds. Experiment 3 was divided into three one-hour time intervals. This method was used to determine the lasting effects of drone radar. Data analysis included the comparison of mean speeds, speed distributions, percent exceeding a given speed, and net speed reductions. The immediate effects of using one radar gun (Experiment 1) were 8-10 mph speed reductions; however, such reductions should not be considered typical effects of radar signal transmission because of the exploratory nature of Experiment 1. Experiment 2 showed that using a radar gun was not effective in reducing vehicle speeds when drivers knew it was drone radar. Experiment 3 indicated that the use of two radar guns increased the effectiveness of drone radars, since drivers were not sure whether the signals were from a police radar or drone radar. The two radar experiments reduced truck speeds by 3-6 mph and car speeds by 3 mph, and the radar effects did not diminish over time. In Experiments 1 and 3 the percentage of vehicles with excessive speeds inside the work zones decreased when radar signals were transmitted. Furthermore, the decreases in Experiment 3 were sustained over a period of time.