Study Details

Study Title: Estimation of the Safety Effects of an Adaptive Traffic Signal Control System

Authors: Ma et al.

Publication Date: JAN, 2015

Abstract: Adaptive traffic signal control (ATSC) is a traffic management strategy in which traffic signal timings change, or adapt, based on observed traffic demand. While ATSC can improve mobility, it also has the potential to reduce crashes since mainline stops are reduced. This paper aims to evaluate the safety effectiveness of ATSC using the Empirical Bayes method. This analysis examines 47 urban or suburban intersections where ATSC was deployed in Virginia using 235 site-years of before data and 66 site-8 years of after data. Installing ATSC was found to produce a crash modification factor (CMF) for total intersection crashes of 0.83 with a standard error of 0.05. This CMF was statistically significant at a 95 percent confidence level. Fatal and injury crashes did not change by a statistically significant amount. Analyses of ATSC safety effects on crash type proportion, by traffic volume level, and by operational improvement magnitude were also performed. All crash types were found to be reduced, but safety benefits vary from corridor to corridor and at different volume levels. It was concluded that ATSC installation can potentially reduce both total and FI crashes at highway intersections, and public agencies should consider both its safety and mobility benefits when justifying ATSC projects.

Study Citation: Ma, J., M. Fontaine, F. Zhou, D. Hale, and Clements, M., "Estimation of the Safety Effects of an Adaptive Traffic Signal Control System." Presented at the 94th Annual Meeting of the Transportation Research Board, Washington, D.C., (2015).

Related Citations: Ma, J., M. Fontaine, F. Zhou, J. Hu, D. Hale, and Clements, M., "Estimation of the Safety Effects of an Adaptive Traffic Signal Control System." Journal of Transportation Engineering, American Association of Civil Engineers, Volume 142, Issue 12 (December 2016).

Study Report: Download the Study Report Document


CMFs Associated With This Study

Category: Intersection traffic control

Countermeasure: Install adaptive traffic signal control

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.83 17 4 Stars All All All Urban and suburban
0.92 8 4 Stars All K,A,B,C All Urban and suburban
0.79 21 4 Stars All All All Urban and suburban
0.92 8 4 Stars All K,A,B,C All Urban and suburban
0.996 0.4 3 Stars All All All Urban and suburban
0.87 13 3 Stars All K,A,B,C All Urban and suburban