Interstate-90 Issues

Overview

Mercer Island is in a unique position as the only City in the region where its citizens' sole means of ingress and egress is by access to an interstate highway.  According to WSDOT 2016 data, on an average weekday, the daily vehicle volumes on the I-90 floating bridge between Mercer Island and Seattle were:

Eastbound: 69,900 vehicles per day
Westbound: 72,800 vehicles per day
Reversible: 15,200 vehicles per day
Total: 157,900 vehicles per day

The I-90 bridge is actually composed of two parallel, named structures, built at different times. The Lacey V. Murrow Memorial Bridge, which now carries the eastbound lanes from Seattle to Mercer Island, was originally completed in 1940, then sank during refurbishment, and was rebuilt in 1993. The westbound traffic, and the reversible express lanes (now being converted to light rail), are carried by the Homer M. Hadley Memorial Bridge, completed in 1989.

Read a Seattle Times overview of the 30-year process leading to the widening of I-90 and the addition of the "Lid" on Mercer Island, or learn more about general bridge history.

Light Rail

When the construction of East Link Light Rail began in mid-2017, the center roadway floating bridge carrying the reversible express lanes was closed permanently to vehicles in order to become the light rail corridor between Seattle and Eastside.
Learn more about the changes to I-90 vehicle access here.
Learn more about light rail on Mercer Island here.