Analysis of Automated Speed Enforcement Cameras in Charlotte, North Carolina

Abstract

The effects of a mobile automated speed enforcement system in Charlotte, North Carolina, were examined. Limited focus groups were conducted to characterize resident and professional attitudes, opinions, and beliefs regarding such a speed program. Overall, opinions were positive. The system, consisting of three mobile units, was implemented along 14 corridors. Two separate analyses were conducted on data collected from January 2000 to December 2005. Findings from a previous study done for the North Carolina Governor's Highway Safety Program were updated. The first, and primary, analysis was a before-and-after analysis of collisions. This study used Hauer's comparison group methodology. Three different collision data sets were analyzed: total collisions, data accounting for regression to the mean, and data for five heavily enforced corridors. On the basis of the analysis, the impact of regression to the mean appears to be negligible. The results indicate that the camera program likely reduced collisions in corridors with automated enforcement. The second analysis observed whether compliance with posted speed limits was enhanced. Mean speeds, median speeds, 85th percentile speeds, and percentages of drivers more than 10 mph over the speed limit were analyzed. The analyses found speed reductions caused by the camera program. On the basis of these findings, it was recommend that the City of Charlotte continue the automated speed enforcement program. Other agencies considering speed camera programs can benefit from the knowledge gained in Charlotte.