Interstate 405 Washington
Interstate 405 north at Downtown Bellevue, Washington. 06/27/15
Overview
Interstate 405 provides a bypass to the east of Seattle, connecting with several major suburbs on the east shore of Lake Washington. The freeway is the most direct route to Redmond, home of Microsoft, via the Washington 520 freeway. As a result of growth in the greater Seattle area, Interstate 405 carries significant traffic volume, almost on a level like its sibling in California, albeit with fewer lanes. To alleviate some of this congestion, a second north-south freeway is being considered for the eastern suburbs of Seattle, dubbed as Interstate 605 by some. It remains unclear if this new highway will be constructed.
High Priority Corridor
Interstate 405 is part of High Priority Corridor 35: FAST Corridor.
History
The original proposal for Interstate 405 around greater Seattle was submitted to the American Association of State Highway Officials (AASHO) in a letter dated July 14, 1958.1 Initial stretches were designated as Washington State Route 405 between Renton and Tukwilla. The first section opened to traffic in September 1965. SR 405 was redesignated I-405 with its completion by 1971.2
Route Information
North End – Lynnwood, WA
South End – Tukwila, WA
Mileage – 30.30
Cities – Tukwila, Renton, Newcastle, Bellevue, Kirkland, Bothell, Lynnwood
- Junctions –
Source: December 31, 2018 Interstate Route Log and Finders List
I-405 Annual Average Daily Traffic (AADT)
Source: 2017 counts obtained from WSDOT Traffic Data Geoportal
State named trailblazers for I-5 and I-405 along the eastbound entrance ramp to SR 518 from Seattle-Tacoma International Airport (SEA). Photo by Jeff Royston (02/24/06).
SR 509 south at the eastbound on-ramp for SR 518 to Seattle-Tacoma International Airport (SEA) and I-5/405. Photo by Chris Elbert (03/03/06).
Highway Guides
North End
– Lynnwood, Washington
North at
South at
South at
North at
South End
– Tukwila, Washington
South at
East at
A left exit connects SR 518 east with I-5 north into Seattle. A lane drop occurs at the ramp for I-5 south to Tacoma while a single lane transitions onto Interstate 405 north to Renton. 06/24/15
North at
South at
Sources:
- Washington State Highway Commission letter to AASHO, dated July 14, 1958, retrieved from AASHTO Route Numbering Archive.
- Interstate 405 (Washington). Wikipedia.org.
Page updated November 7, 2020.