Study Details

Study Title: Estimating the Longer-Term Safety Effects of Speed Enforcement Cameras in Charlotte, NC

Authors: Moon and Hummer

Publication Date: JAN, 2010

Abstract: The City of Charlotte, North Carolina conducted a pilot evaluation of the safety effect of speed enforcement cameras. The City selected fourteen key corridors with high collisions, and an automated speed enforcement camera program was implemented in the corridors scattered throughout Charlotte from September 2004 through July 2006. In addition to comparing the net safety effectiveness before and after implementing automated speed cameras, this study estimated long-term collision patterns from the speed enforcement program with the carry-over safety effects after its termination by using an autoregreesive integrated moving average (ARIMA) intervention analysis as well as using a before-after analysis with comparison sites. The fitted ARIMA intervention model indicates that the treatment corridors demonstrated a significant reduction in collisions over the study periods. Furthermore, the speed camera program appeared to have significant carry-over effects into the "postintervention" period, but collisions were slowly returning to the original levels. The before-after analysis with comparison sites also provided evidence that the effect of the speed camera program was a decrease in collisions into the post-intervention period.

Study Citation: Moon, J.P. and J. E. Hummer. "Estimating the Longer-Term Safety Effects of Speed Enforcement Cameras in Charlotte, NC." TRB 89th Annual Meeting Compendium of Papers CD-ROM. Washington, D.C. 2010.


CMFs Associated With This Study

Category: Advanced technology and ITS

Countermeasure: Implement automated speed enforcement cameras

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.84 16.2 3 Stars All All Not Specified
0.82 18.2 2 Stars All O Not Specified
0.85 15.1 2 Stars All K,A,B,C Not Specified

Countermeasure: Media coverage of automated speed enforcement cameras

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.92 8 2 Stars All All Not Specified
0.91 8.6 2 Stars All O Not Specified
0.9 10.2 2 Stars All K,A,B,C Not Specified

Countermeasure: Removal of automated speed enforcement cameras (compared to after implementation)

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.97 3.4 2 Stars All All Not Specified
0.96 3.9 2 Stars All O Not Specified
0.98 2.1 2 Stars All K,A,B,C Not Specified

Countermeasure: Removal of automated speed enforcement cameras (compared to before implementation)

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.81 18.9 3 Stars All All Local
0.79 21.3 3 Stars All O Not Specified
0.83 16.7 2 Stars All K,A,B,C Not Specified