Evaluating the Safety Impacts of Flashing Yellow Permissive Left-Turn Indications in Massachusetts: Approach-Level Analysis
Funding Source: MassDOT
Title: Evaluating the Safety Impacts of Flashing Yellow Permissive Left-Turn Indications in Massachusetts: Approach-Level Analysis
Date: March 2023
Status: Completed
Summary: Given the novelty of the Flashing Yellow Arrow (FYA) in Massachusetts, this research study provides MassDOT with a greater understanding of their impacts from an approach-level perspective. More so, this study provides the agency with a holistic overview of infrastructure and operational impacts at each of these intersections, ultimately leading to an improved understanding of future design characteristics. Approach-level analyses remain the most appropriate method to assess the true impact of the permissive indication as well as infrastructure (e.g., turn lane length, LT lane offset, etc.) and operational (e.g., clearance intervals, phase sequence, etc.) elements. This study evaluated the before and after crashes at 200 statewide FYA intersections from an approach level to better understand the safety impacts of the LT permissive FYA signal. The advancement of these crash data analytics, methodologies, and applications will continue to remain important in years to come and will increase safety by providing an increased understanding of conflict risk at signalized intersections involving FYAs.
