The Third Lake Washington Bridge, officially the Homer M. Hadley Memorial Bridge, is the fifth-longest floating bridge in the world, at 5,811 feet (1772 m). It carries the westbound and reversible lanes of Interstate 90 across Lake Washington between Mercer Island, Washington, and Seattle Washington.
The bridge was built in 1989 and is named for Homer More Hadley, who designed the bridge's companion span, the Lacey V. Murrow Memorial Bridge.
When the bridge was built, parallel to the Lacey V. Murrow Memorial Bridge, two reversible high-occupancy vehicle (HOV) lanes were set up to accommodate the traffic flow between Seattle and the suburban Eastside (westbound in the morning, eastbound in the evenings). Unfortunately, because the lanes are reversible, this pushes all the HOV traffic going on one side (depending on what time it is) to the general-purpose lanes. This has been a huge problem with the increasing amount of traffic congestion in Seattle, Mercer Island and Bellevue, Washington.
Currently, Sound Transit and the Washington State Department of Transportation are relocating HOV lanes from the reversible express lanes to the eastbound and westbound lanes of Interstate 90. This move is necessary to accommodate the East Link light-rail line (under construction) from downtown Seattle to Bellevue and Redmond, Washington. The first phase is expected to be completed in 2009. East Link, scheduled for full completion in 2020, will be the first time that a light-rail line will operate on a floating bridge.
The bridge includes two reversible lanes, which normally carry westbound traffic on weekday mornings and eastbound traffic at other times. Use of the reversible express lanes is restricted to HOV traffic, except for vehicles traveling to and from Mercer Island.
With a total of five traffic lanes and three full-sized shoulders, the Third Lake Washington Bridge is the widest floating bridge in the world.
Most local residents have never heard of the Hadley name[] and refer to both bridges together as "the Mercer Island Bridge". Some also refer to the "Old" and "New" Mercer Island Bridges, but these terms are ambiguous because the Murrow bridge was rebuilt after the Hadley bridge was completed.