Changes in Traffic Patterns and Air Quality Along Mystic Avenue in Medford and Somerville, Massachusetts, After Installation of an Intermittent Bus Lane

The City of Medford, MA, (pop. 60,000) and the City of Somerville (pop. 76,000) immediately to the south are home to several major roadways including Interstate 93 and Massachusetts State Highways 28 and 38. These are among the busiest roadways in the Boston metropolitan area, together carrying over 240,000 vehicles per day through the two cities (Boston MPO, 2022). In an effort to increase bus efficiency, reduce traffic burden, and improve air quality in their communities, Medford and Somerville tested a bus lane with intermittent prioritization on Massachusetts Bay Transportation Authority (MBTA) bus route #95, which runs along Route 38 (Mystic Avenue) within the two cities.

The goal of this study was to determine whether the bus lane on Mystic Avenue caused short term (months) changes in traffic patterns and improved air quality along the length of the bus lane.