TY - JOUR
T1 - Safety evaluation of continuous green T intersections
T2 - A propensity scores-genetic matching-potential outcomes approach
AU - Wood, Jonathan
AU - Donnell, Eric T.
N1 - Funding Information:
The authors would like to acknowledge the Federal Highway Administration, Office of Safety Research and Development for supporting this research. The FHWA Contracting Officer’s Technical Manager for this project was Roya Amjadi. Further, the project team gratefully acknowledges the participation of Mr. Joe Santos, P.E., Florida Department of Transportation, for supplying data used in the project evaluation. Mr. Joey Riddle, P.E., and Ms. Jennifer Oswalt-Rhoades, P.E., from the South Carolina Department of Transportation, also supplied data used in the evaluation, and their support is gratefully acknowledged.
Publisher Copyright:
© 2016 Elsevier Ltd. All rights reserved.
PY - 2016/8/1
Y1 - 2016/8/1
N2 - The continuous green T intersection is characterized by a channelized left-turn movement from the minor street approach onto the major street, along with a continuous through movement on the major street. The continuous flow through movement is not controlled by the three-phase traffic signal that is used to separate all other movements at the intersection. Rather, the continuous through movement typically has a green through arrow indicator to inform drivers that they do not have to stop. Past research has consistently shown that there are operational and environmental benefits to implementing this intersection form at three-leg locations, when compared to a conventional signalized intersection. These benefits include reduced delay, fuel consumption, and emissions. The safety effects of the conventional green T intersection are less clear. Past research has been limited to small sample sizes, or utilized only statistical comparisons reported crashes to evaluate the safety performance relative to similar intersection types. The present study overcomes past safety research evaluations by using a propensity scores-potential outcomes framework, with genetic matching, to compare the safety performance of the continuous green T to conventional signalized intersections, using treatment and comparison site data from Florida and South Carolina. The results show that the expected total, fatal and injury, and target crash (rear-end, angle, and sideswipe) frequencies are lower at the continuous green T intersection relative to the conventional signalized intersection (CMFs of 0.958 [95% CI = 0.772-1.189], 0.846 [95% CI = 0.651-1.099], and 0.920 [95% CI = 0.714-1.185], respectively).
AB - The continuous green T intersection is characterized by a channelized left-turn movement from the minor street approach onto the major street, along with a continuous through movement on the major street. The continuous flow through movement is not controlled by the three-phase traffic signal that is used to separate all other movements at the intersection. Rather, the continuous through movement typically has a green through arrow indicator to inform drivers that they do not have to stop. Past research has consistently shown that there are operational and environmental benefits to implementing this intersection form at three-leg locations, when compared to a conventional signalized intersection. These benefits include reduced delay, fuel consumption, and emissions. The safety effects of the conventional green T intersection are less clear. Past research has been limited to small sample sizes, or utilized only statistical comparisons reported crashes to evaluate the safety performance relative to similar intersection types. The present study overcomes past safety research evaluations by using a propensity scores-potential outcomes framework, with genetic matching, to compare the safety performance of the continuous green T to conventional signalized intersections, using treatment and comparison site data from Florida and South Carolina. The results show that the expected total, fatal and injury, and target crash (rear-end, angle, and sideswipe) frequencies are lower at the continuous green T intersection relative to the conventional signalized intersection (CMFs of 0.958 [95% CI = 0.772-1.189], 0.846 [95% CI = 0.651-1.099], and 0.920 [95% CI = 0.714-1.185], respectively).
UR - http://www.scopus.com/inward/record.url?scp=84964788363&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84964788363&partnerID=8YFLogxK
U2 - 10.1016/j.aap.2016.04.015
DO - 10.1016/j.aap.2016.04.015
M3 - Article
C2 - 27129112
AN - SCOPUS:84964788363
VL - 93
SP - 1
EP - 13
JO - Accident Analysis and Prevention
JF - Accident Analysis and Prevention
SN - 0001-4575
ER -