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(%) Quality Crash Type Crash Severity Roadway Type Area Type
1.136 -13.6 4 Stars Vehicle/pedestrian All All
1.031 -3.1 4 Stars Other All All
0.89 11 4 Stars Other K,A,B,C All
0.718 28.2 3 Stars Vehicle/pedestrian All All
0.672 32.8 4 Stars Other All All
0.788 21.2 4 Stars Other K,A,B,C All
1.106 -10.6 4 Stars Vehicle/pedestrian All All
1.025 -2.5 4 Stars Other All All
0.951 4.9 4 Stars Other K,A,B,C All
1.091 -9.1 4 Stars Vehicle/pedestrian All All
1.023 -2.3 4 Stars Other All All
0.942 5.8 5 Stars Other K,A,B,C All

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

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.9 10 4 Stars All All All Urban and suburban
0.83 17 4 Stars All K,A,B,C All Urban and suburban
0.81 19 4 Stars Vehicle/pedestrian All All Urban and suburban
0.9 10 4 Stars All All All Urban and suburban
0.85 15 4 Stars All K,A,B,C All Urban and suburban
0.81 19 4 Stars Vehicle/pedestrian All All Urban and suburban
0.83 17 4 Stars All All All Urban and suburban
0.72 28 4 Stars All K,A,B,C All Urban and suburban
0.9 10 3 Stars Vehicle/pedestrian All All Urban and suburban
0.84 16 4 Stars All All All Urban and suburban
0.86 14 4 Stars All K,A,B,C All Urban and suburban
0.91 9 4 Stars Vehicle/pedestrian All All Urban and suburban
0.9 10 4 Stars All All All Urban and suburban
1.09 -9 3 Stars All K,A,B,C All Urban and suburban
0.54 46 3 Stars Vehicle/pedestrian All All Urban and suburban
0.87 13 5 Stars All All All Urban and suburban
0.86 14 5 Stars All K,A,B,C All Urban and suburban
0.87 13 5 Stars Vehicle/pedestrian All All Urban and suburban