Study Details

Study Title: Safety Evaluation of Protected Left-Turn Phasing and Leading Pedestrian Intervals on Pedestrian Safety

Authors: Goughnour et al.

Publication Date:OCT, 2018

Abstract: The objective of the study was to evaluate the safety effects of two countermeasures with respect to vehicle–pedestrian crashes—the provision of protected or protected/permissive left-turn phasing and the provision of leading pedestrian intervals (LPIs)—using a before–after empirical Bayesian methodology. The study used data from North American cities that had installed one or both of the countermeasures of interest, including Chicago, IL; New York City, NY; Charlotte, NC; and Toronto, ON. This study showed that the provision of protected left-turn phasing reduced vehicle–vehicle injury crashes but did not produce statistically significant results for vehicle–pedestrian crashes overall. A disaggregate analysis of the effect of protected or protected/permissive left-turn phasing on vehicle–pedestrian crashes indicated that this strategy may be more beneficial when there are higher pedestrian and vehicle volumes, particularly above 5,500 pedestrians per day. At these high-volume locations, the left-turn phasing evaluation resulted in a potential benefit–cost (B/C) ratio range of 1:15.6::1:38.9. The evaluation of LPIs showed that the countermeasure reduced vehicle–pedestrian crashes. This evaluation produced a crash modification factor of 0.87 with a potential B/C ratio range of 1:207::1:517.

Study Citation: Goughnour, E., D. Carter, C. Lyon, B. Persaud, B. Lan, P. Chun, I. Hamilton, and K. Signor. "Safety Evaluation of Protected Left-Turn Phasing and Leading Pedestrian Intervals on Pedestrian Safety." Report No. FHWA-HRT-18-044. Federal Highway Administration. (October 2018)


CMFs Associated With This Study

Category: Intersection traffic control

Countermeasure: Change permissive left-turn phasing to protected only or protected/permissive

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
1.136-13.64 StarsVehicle/pedestrianAllAll
1.031-3.14 StarsOtherAllAll
0.89114 StarsOtherK,A,B,CAll
0.71828.24 StarsVehicle/pedestrianAllAll
0.67232.85 StarsOtherAllAll
0.78821.24 StarsOtherK,A,B,CAll
1.106-10.65 StarsVehicle/pedestrianAllAll
1.025-2.55 StarsOtherAllAll
0.9514.95 StarsOtherK,A,B,CAll
1.091-9.14 StarsVehicle/pedestrianAllAll
1.023-2.34 StarsOtherAllAll
0.9425.85 StarsOtherK,A,B,CAll

Countermeasure: Modify signal phasing (implement a leading pedestrian interval)

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.9105 StarsAllAllAllUrban and suburban
0.83175 StarsAllK,A,B,CAllUrban and suburban
0.81195 StarsVehicle/pedestrianAllAllUrban and suburban
0.9105 StarsAllAllAllUrban and suburban
0.85155 StarsAllK,A,B,CAllUrban and suburban
0.81195 StarsVehicle/pedestrianAllAllUrban and suburban
0.83175 StarsAllAllAllUrban and suburban
0.72284 StarsAllK,A,B,CAllUrban and suburban
0.9104 StarsVehicle/pedestrianAllAllUrban and suburban
0.84165 StarsAllAllAllUrban and suburban
0.86145 StarsAllK,A,B,CAllUrban and suburban
0.9194 StarsVehicle/pedestrianAllAllUrban and suburban
0.9104 StarsAllAllAllUrban and suburban
1.09-94 StarsAllK,A,B,CAllUrban and suburban
0.54463 StarsVehicle/pedestrianAllAllUrban and suburban
0.87135 StarsAllAllAllUrban and suburban
0.86145 StarsAllK,A,B,CAllUrban and suburban
0.87135 StarsVehicle/pedestrianAllAllUrban and suburban