Safety Evaluation of Continuous Green T Intersections

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This document is a technical summary of the Federal Highway Administration report, Safety Evaluation of Continuous Green T Intersections (FHWA-HRT-16-036).⁽¹⁾

OBJECTIVE

The Federal Highway Administration (FHWA) organized 40 States to participate in the FHWA Evaluation of Low-Cost Safety Improvements Pooled Fund Study as part of its strategic highway safety plan support effort. The purpose of the study was to evaluate the safety effectiveness of low-cost safety improvement strategies through scientifically rigorous crash-based studies. One of the strategies evaluated for this study is the use of continuous green T (CGT) intersections at three-leg locations. This treatment allows for a continuous through movement on the major street with a channelized left-turn movement from the minor street onto the major street.

Past research has shown that environmental and operational benefits of CGT intersections, when compared with conventional signalized intersections, include reductions in delay, fuel consumption, and emissions.^(2,3) Research on the safety effects of CGT intersections has been limited in scope and statistical significance.

This study sought to fill this knowledge gap by examining the safety effectiveness of CGT intersections in terms of crash frequency using the propensity scores-potential outcomes framework. A benefit-cost (B/C) analysis compared the safety benefits to the construction costs of a CGT relative to a conventional signalized three-leg intersection.