Most of Mercer Island’s streets are two lane residential streets with low to moderate volumes of traffic. Island Crest Way, a north-south arterial which runs the length of the Island, is an exception because it is a principal feeder route to I-90 and the Town Center. East and West Mercer Way ring the Island and provide two more connections with I-90. SE 40th Street and Gallagher Hill Road also carry high traffic volumes in the north-central portion of the Island. In addition to arterial streets, the local street network provides access to private residences and properties. Public transit serves the Mercer Island Park and Ride and other locations on the Island.
Mercer Island has over 56 miles of trails, sidewalks and bicycle lanes for non-motorized travel. A regional trail runs across the north end of the Island along the I-90 corridor providing a convenient connection to Seattle and Bellevue for pedestrians and bicyclists.