Study Details

Study Title: A Before-and-After Empirical Bayes Evaluation of Automated Mobile Speed Enforcement on Urban Arterial Roads

Authors: Li et al.

Publication Date: JAN, 2015

Abstract: Speeding is a leading factor in road collisions and is found to contribute to approximately one third of fatal collisions. Speed enforcement is one of the most common countermeasures used to reduce speed. However, a gap exists in the literature regarding the effectiveness of automated mobile photo enforcement on urban arterial roads. This study addresses this gap using the before-and-after Empirical Bayes (EB) method to account for regression-to-the-mean effects and other confounding factors. Locally developed safety performance functions and yearly calibration factors for different collision severities were obtained using a reference group of urban arterial roads. The evaluation period covers eight years, and collision records, deployment information, traffic counts, and road geometric data were collected. The results showed consistent reductions in different collision severities, ranging from 14% to 20%, with the highest reductions observed for severe collisions. The enforced segments were further categorized according to site selection criteria and deployment hours to examine their effects on collision reduction. More reductions were found at segments that had more collisions during the before period and longer deployment hours. The study also compared the safety effects of continuous and discontinuous enforcement strategies on different arterials, and the analysis revealed that continuous enforcement achieved more reductions in all severities/types of collisions. Moreover, the study also investigated the spillover effects on adjacent unenforced approaches. Significant reductions were found, and the results were discussed with regard to the general and specific deterrence of the enforcement.

Study Citation: Li, R., K. El-Basyouny, and A. Kim. "A Before-and-After Empirical Bayes Evaluation of Automated Mobile Speed Enforcement on Urban Arterial Roads". Presented at the 94th Annual Meeting of the Transportation Research Board, Paper No. 15-1563, Washington, D.C., (2015).


CMFs Associated With This Study

Category: Advanced technology and ITS

Countermeasure: Implement mobile automated speed enforcement system

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.799 20.1 5 Stars All K,A,B,C Principal Arterial Other Urban
0.857 14.3 5 Stars All O Principal Arterial Other Urban
0.855 14.5 5 Stars All All Principal Arterial Other Urban
0.821 17.9 5 Stars Speed related O Principal Arterial Other Urban
0.815 18.5 5 Stars Speed related All Principal Arterial Other Urban
0.849 15.1 3 Stars All K,A,B,C Principal Arterial Other Urban
0.729 27.1 3 Stars All K,A,B,C Principal Arterial Other Urban
0.809 19.1 3 Stars All K,A,B,C Principal Arterial Other Urban
0.917 8.3 3 Stars All O Principal Arterial Other Urban
0.864 13.6 3 Stars All O Principal Arterial Other Urban
0.834 16.6 3 Stars All O Principal Arterial Other Urban
0.971 2.9 3 Stars All All Principal Arterial Other Urban
0.929 7.1 3 Stars All All Principal Arterial Other Urban
0.806 19.4 3 Stars All All Principal Arterial Other Urban
0.712 28.8 4 Stars Speed related O Principal Arterial Other Urban
0.939 6.1 3 Stars Speed related O Principal Arterial Other Urban
0.798 20.2 4 Stars Speed related O Principal Arterial Other Urban
0.833 16.7 3 Stars Speed related All Principal Arterial Other Urban
0.865 13.5 3 Stars Speed related All Principal Arterial Other Urban
0.785 21.5 3 Stars Speed related All Principal Arterial Other Urban
0.873 12.7 3 Stars All K,A,B,C Principal Arterial Other Urban
0.738 26.2 3 Stars All K,A,B,C Principal Arterial Other Urban
0.808 19.2 3 Stars All K,A,B,C Principal Arterial Other Urban
0.833 16.7 3 Stars All O Principal Arterial Other Urban
0.726 27.4 3 Stars All O Principal Arterial Other Urban
0.945 5.5 3 Stars All O Principal Arterial Other Urban
0.837 16.3 3 Stars All All Principal Arterial Other Urban
0.735 26.5 3 Stars All All Principal Arterial Other Urban
0.936 6.4 3 Stars All All Principal Arterial Other Urban
0.753 24.7 4 Stars Speed related O Principal Arterial Other Urban
0.695 30.5 4 Stars Speed related O Principal Arterial Other Urban
0.924 7.6 3 Stars Speed related O Principal Arterial Other Urban
0.774 22.6 3 Stars Speed related All Principal Arterial Other Urban
0.699 30.1 3 Stars Speed related All Principal Arterial Other Urban
0.905 9.5 3 Stars Speed related All Principal Arterial Other Urban
0.859 14.1 3 Stars All K,A,B,C Principal Arterial Other Urban
0.75 25 3 Stars All K,A,B,C Principal Arterial Other Urban
0.776 22.4 3 Stars All K,A,B,C Principal Arterial Other Urban
1.035 -3.5 3 Stars All O Principal Arterial Other Urban
0.795 20.5 3 Stars All O Principal Arterial Other Urban
0.826 17.4 3 Stars All O Principal Arterial Other Urban
1.018 -1.8 3 Stars All All Principal Arterial Other Urban
0.771 22.9 3 Stars All All Principal Arterial Other Urban
0.826 17.4 3 Stars All All Principal Arterial Other Urban
0.94 6 3 Stars Speed related O Principal Arterial Other Urban
0.806 19.4 4 Stars Speed related O Principal Arterial Other Urban
0.773 22.7 4 Stars Speed related O Principal Arterial Other Urban
0.955 4.5 3 Stars Speed related All Principal Arterial Other Urban
0.769 23.1 3 Stars Speed related All Principal Arterial Other Urban
0.78 22 3 Stars Speed related All Principal Arterial Other Urban
0.938 6.2 3 Stars All K,A,B,C Principal Arterial Other Urban
0.771 22.9 3 Stars All K,A,B,C Principal Arterial Other Urban
0.727 27.3 3 Stars All K,A,B,C Principal Arterial Other Urban
0.856 14.4 3 Stars All O Principal Arterial Other Urban
0.932 6.8 3 Stars All O Principal Arterial Other Urban
0.815 18.5 3 Stars All O Principal Arterial Other Urban
0.87 13 3 Stars All All Principal Arterial Other Urban
0.915 8.5 3 Stars All All Principal Arterial Other Urban
0.811 18.9 3 Stars All All Principal Arterial Other Urban
0.893 10.7 3 Stars Speed related O Principal Arterial Other Urban
0.847 15.3 3 Stars Speed related O Principal Arterial Other Urban
0.763 23.7 3 Stars Speed related O Principal Arterial Other Urban
0.883 11.7 3 Stars Speed related All Principal Arterial Other Urban
0.844 15.6 3 Stars Speed related All Principal Arterial Other Urban
0.759 24.1 3 Stars Speed related All Principal Arterial Other Urban
0.828 17.2 3 Stars All K,A,B,C Principal Arterial Other Urban
0.888 11.2 3 Stars All K,A,B,C Principal Arterial Other Urban
0.709 29.1 3 Stars All K,A,B,C Principal Arterial Other Urban
0.851 14.9 3 Stars All O Principal Arterial Other Urban
0.9 10 3 Stars All O Principal Arterial Other Urban
0.832 16.8 3 Stars All O Principal Arterial Other Urban
0.862 13.8 3 Stars All All Principal Arterial Other Urban
0.904 9.6 3 Stars All All Principal Arterial Other Urban
0.817 18.3 3 Stars All All Principal Arterial Other Urban
0.893 10.7 3 Stars Speed related O Principal Arterial Other Urban
0.794 20.6 3 Stars Speed related O Principal Arterial Other Urban
0.786 21.4 3 Stars Speed related O Principal Arterial Other Urban
0.884 11.6 3 Stars Speed related All Principal Arterial Other Urban
0.819 18.1 3 Stars Speed related All Principal Arterial Other Urban
0.766 23.4 3 Stars Speed related All Principal Arterial Other Urban
0.679 32.1 4 Stars All K,A,B,C Principal Arterial Other Urban
0.713 28.7 4 Stars All O Principal Arterial Other Urban
0.723 27.7 4 Stars All All Principal Arterial Other Urban
0.727 27.3 4 Stars Speed related O Principal Arterial Other Urban
0.733 26.7 4 Stars Speed related All Principal Arterial Other Urban
0.821 17.9 4 Stars All K,A,B,C Principal Arterial Other Urban
0.915 8.5 4 Stars All O Principal Arterial Other Urban
0.914 8.6 4 Stars All All Principal Arterial Other Urban
0.85 15 4 Stars Speed related O Principal Arterial Other Urban
0.866 13.4 4 Stars Speed related All Principal Arterial Other Urban
0.739 26.1 4 Stars All K,A,B,C Principal Arterial Other Urban
0.982 1.8 4 Stars All O Principal Arterial Other Urban
0.955 4.5 4 Stars All All Principal Arterial Other Urban
0.908 9.2 4 Stars Speed related O Principal Arterial Other Urban
0.86 14 5 Stars Speed related All Principal Arterial Other Urban
0.975 2.5 4 Stars All K,A,B,C Principal Arterial Other Urban
0.854 14.6 5 Stars All O Principal Arterial Other Urban
0.859 14.1 5 Stars All All Principal Arterial Other Urban
0.846 15.4 4 Stars Speed related O Principal Arterial Other Urban
0.889 11.1 4 Stars Speed related All Principal Arterial Other Urban