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(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.78621.43 StarsSpeed relatedOPrincipal Arterial OtherUrban
0.88411.63 StarsSpeed relatedAllPrincipal Arterial OtherUrban
0.81918.13 StarsSpeed relatedAllPrincipal Arterial OtherUrban
0.76623.43 StarsSpeed relatedAllPrincipal Arterial OtherUrban
0.67932.14 StarsAllK,A,B,CPrincipal Arterial OtherUrban
0.71328.74 StarsAllOPrincipal Arterial OtherUrban
0.72327.74 StarsAllAllPrincipal Arterial OtherUrban
0.72727.34 StarsSpeed relatedOPrincipal Arterial OtherUrban
0.73326.74 StarsSpeed relatedAllPrincipal Arterial OtherUrban
0.82117.94 StarsAllK,A,B,CPrincipal Arterial OtherUrban
0.9158.54 StarsAllOPrincipal Arterial OtherUrban
0.9148.64 StarsAllAllPrincipal Arterial OtherUrban
0.85154 StarsSpeed relatedOPrincipal Arterial OtherUrban
0.86613.44 StarsSpeed relatedAllPrincipal Arterial OtherUrban
0.73926.14 StarsAllK,A,B,CPrincipal Arterial OtherUrban
0.9821.84 StarsAllOPrincipal Arterial OtherUrban
0.9554.54 StarsAllAllPrincipal Arterial OtherUrban
0.9089.24 StarsSpeed relatedOPrincipal Arterial OtherUrban
0.86145 StarsSpeed relatedAllPrincipal Arterial OtherUrban
0.9752.54 StarsAllK,A,B,CPrincipal Arterial OtherUrban
0.85414.65 StarsAllOPrincipal Arterial OtherUrban
0.85914.15 StarsAllAllPrincipal Arterial OtherUrban
0.84615.44 StarsSpeed relatedOPrincipal Arterial OtherUrban
0.88911.14 StarsSpeed relatedAllPrincipal Arterial OtherUrban
1.035-3.53 StarsAllOPrincipal Arterial OtherUrban
0.79520.53 StarsAllOPrincipal Arterial OtherUrban
0.82617.43 StarsAllOPrincipal Arterial OtherUrban
1.018-1.83 StarsAllAllPrincipal Arterial OtherUrban
0.77122.93 StarsAllAllPrincipal Arterial OtherUrban
0.82617.43 StarsAllAllPrincipal Arterial OtherUrban
0.9463 StarsSpeed relatedOPrincipal Arterial OtherUrban
0.80619.44 StarsSpeed relatedOPrincipal Arterial OtherUrban
0.77322.74 StarsSpeed relatedOPrincipal Arterial OtherUrban
0.9554.53 StarsSpeed relatedAllPrincipal Arterial OtherUrban
0.76923.13 StarsSpeed relatedAllPrincipal Arterial OtherUrban
0.78223 StarsSpeed relatedAllPrincipal Arterial OtherUrban
0.9386.23 StarsAllK,A,B,CPrincipal Arterial OtherUrban
0.77122.93 StarsAllK,A,B,CPrincipal Arterial OtherUrban
0.72727.33 StarsAllK,A,B,CPrincipal Arterial OtherUrban
0.85614.43 StarsAllOPrincipal Arterial OtherUrban
0.9326.83 StarsAllOPrincipal Arterial OtherUrban
0.81518.53 StarsAllOPrincipal Arterial OtherUrban
0.87133 StarsAllAllPrincipal Arterial OtherUrban
0.9158.53 StarsAllAllPrincipal Arterial OtherUrban
0.81118.93 StarsAllAllPrincipal Arterial OtherUrban
0.89310.73 StarsSpeed relatedOPrincipal Arterial OtherUrban
0.84715.33 StarsSpeed relatedOPrincipal Arterial OtherUrban
0.76323.73 StarsSpeed relatedOPrincipal Arterial OtherUrban
0.88311.73 StarsSpeed relatedAllPrincipal Arterial OtherUrban
0.84415.63 StarsSpeed relatedAllPrincipal Arterial OtherUrban
0.75924.13 StarsSpeed relatedAllPrincipal Arterial OtherUrban
0.82817.23 StarsAllK,A,B,CPrincipal Arterial OtherUrban
0.88811.23 StarsAllK,A,B,CPrincipal Arterial OtherUrban
0.70929.13 StarsAllK,A,B,CPrincipal Arterial OtherUrban
0.85114.93 StarsAllOPrincipal Arterial OtherUrban
0.9103 StarsAllOPrincipal Arterial OtherUrban
0.83216.83 StarsAllOPrincipal Arterial OtherUrban
0.86213.83 StarsAllAllPrincipal Arterial OtherUrban
0.9049.63 StarsAllAllPrincipal Arterial OtherUrban
0.81718.33 StarsAllAllPrincipal Arterial OtherUrban
0.89310.73 StarsSpeed relatedOPrincipal Arterial OtherUrban
0.79420.63 StarsSpeed relatedOPrincipal Arterial OtherUrban
0.79920.15 StarsAllK,A,B,CPrincipal Arterial OtherUrban
0.85714.35 StarsAllOPrincipal Arterial OtherUrban
0.85514.55 StarsAllAllPrincipal Arterial OtherUrban
0.82117.95 StarsSpeed relatedOPrincipal Arterial OtherUrban
0.81518.55 StarsSpeed relatedAllPrincipal Arterial OtherUrban
0.84915.13 StarsAllK,A,B,CPrincipal Arterial OtherUrban
0.72927.13 StarsAllK,A,B,CPrincipal Arterial OtherUrban
0.80919.13 StarsAllK,A,B,CPrincipal Arterial OtherUrban
0.9178.33 StarsAllOPrincipal Arterial OtherUrban
0.86413.63 StarsAllOPrincipal Arterial OtherUrban
0.83416.63 StarsAllOPrincipal Arterial OtherUrban
0.9712.93 StarsAllAllPrincipal Arterial OtherUrban
0.9297.13 StarsAllAllPrincipal Arterial OtherUrban
0.80619.43 StarsAllAllPrincipal Arterial OtherUrban
0.71228.84 StarsSpeed relatedOPrincipal Arterial OtherUrban
0.9396.13 StarsSpeed relatedOPrincipal Arterial OtherUrban
0.79820.24 StarsSpeed relatedOPrincipal Arterial OtherUrban
0.83316.73 StarsSpeed relatedAllPrincipal Arterial OtherUrban
0.86513.53 StarsSpeed relatedAllPrincipal Arterial OtherUrban
0.78521.53 StarsSpeed relatedAllPrincipal Arterial OtherUrban
0.87312.73 StarsAllK,A,B,CPrincipal Arterial OtherUrban
0.73826.23 StarsAllK,A,B,CPrincipal Arterial OtherUrban
0.80819.23 StarsAllK,A,B,CPrincipal Arterial OtherUrban
0.83316.73 StarsAllOPrincipal Arterial OtherUrban
0.72627.43 StarsAllOPrincipal Arterial OtherUrban
0.9455.53 StarsAllOPrincipal Arterial OtherUrban
0.83716.33 StarsAllAllPrincipal Arterial OtherUrban
0.73526.53 StarsAllAllPrincipal Arterial OtherUrban
0.9366.43 StarsAllAllPrincipal Arterial OtherUrban
0.75324.74 StarsSpeed relatedOPrincipal Arterial OtherUrban
0.69530.54 StarsSpeed relatedOPrincipal Arterial OtherUrban
0.9247.63 StarsSpeed relatedOPrincipal Arterial OtherUrban
0.77422.63 StarsSpeed relatedAllPrincipal Arterial OtherUrban
0.69930.13 StarsSpeed relatedAllPrincipal Arterial OtherUrban
0.9059.53 StarsSpeed relatedAllPrincipal Arterial OtherUrban
0.85914.13 StarsAllK,A,B,CPrincipal Arterial OtherUrban
0.75253 StarsAllK,A,B,CPrincipal Arterial OtherUrban
0.77622.43 StarsAllK,A,B,CPrincipal Arterial OtherUrban