Interstate 405 Washington

Interstate 405 Washington
I-405 north - Bellevue, WA

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 urban loop is the most direct route to Redmond, home of Microsoft, via the freeway along State Route 520. As a result of growth in the greater Seattle area, Interstate 405 carries significant traffic volume, almost on a level like I-405 in California, albeit with fewer lanes.

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 as I-405 with its completion by 1971.2

Seattle inset on the 1967 Washington Official Highway Map

Interstate 405 completed north to Bellevue on the 1967 Official Washington Highway Map

Route Information

  • North End – Lynnwood, WA

  • South End – Tukwila, WA

  • Mileage – 30.30

  • Cities – Tukwila, Renton, Newcastle, Bellevue, Kirkland, Bothell, Lynnwood

  • Junctions – I-5 I-90

Source: December 31, 2021 Interstate Route Log and Finders List

I-405 Annual Average Daily Traffic (AADT)

Source: 2017 AADT – WSDOT Traffic Data Geoportal

I-90/405 trailblazers on SR 518

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 SR 518 - Burien, WA

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).

1967 AAA map for Seattle, Washington

Interstate 405 temporary designated as State Route 405 north of Bellevue in 1967

 Photo Guides

North End I-5 Washington 525 – Lynnwood, Washington

I-405 North at I-5 SR 525

I-405 north one mile from I-5 at Alderwood Manor, Washington

Interstate 405 weaves northward between the Alderwood Manor and Martha Lake communities 2.9 miles from SR 527 to SR 525 and I-5. 07/19/23

I-405 north next meets I-5 north to Everett, Washington

The unnumbered ramp for I-5 north departs next for Everett and Vancouver, British Columbia. 07/19/23

I-405 north transitions to SR 525 in a half mile at I-5 and Lynnwood, WA

Interstate 5 heads north from I-405 at Martha Lake to Everett, Marysville and Bellingham. SR 525 extends the freeway northwest to SR 99 en route to Mukilteo. 07/19/23

I-405 north at I-5/SR 525 - Martha Lake, WA

The right lane drops at the loop ramp for southbound Interstate 5 to Lynwood and Seattle. Two lanes transition onto northbound SR 525. 08/29/06

I-405 north at I-5/SR 525 - Lynwood, WA

An end shield is posted for Interstate 405 along with a begin SR 525 shield. 08/29/06

I-405 north at I-5/SR 525 - Lynwood, WA

Interstate 5 angles southwest through Lynwood to Mountlake Terrace and Shoreline before reaching the Seattle city limits. 08/29/06

SR 525 South at I-5 I-405

SR 525 south passes under 164th St SW on the 1.5 miles to I-5/405

1.5 miles north of I-5 south and I-405 south on SR 525 at North Lynnwood. 07/20/23

SR 525 heads a half mile south from Alderwood Mall Pkwy to I-5/405

The next exit along SR 525 south is the connection for Interstate 5 southbound to Seattle. 07/20/23

SR 525 runs along the Lynnwood city line southeast to I-5/405

The entrance ramp from Alderwood Mall Parkway forms an auxiliary lane along SR 525 to I-5 south. 07/20/23

SR 525 south at I-5 south to Seattle, Washington

Beyond the exit ramp to I-5 south, SR 525 transitions into Interstate 405. There is no access to I-5 north in this direction. 07/20/23

SR 525 end and I-405 begin shields posted above Interstate 5

Interstate 405 begins at the south end of Washington State Route 525 above I-5. 07/20/23

I-5 South at I-405

I-5 south at Martha Lake, Washington two miles from I-405/SR 525

Interstate 5 advances south through a six-ramp parclo interchange (Exit 183) with 164th Street SW at Martha Lake ahead of I-405. 07/19/23

I-5 south at 164th St SW, one mile from I-405/SR 525 at Martha Lake, WA

An HOV ramp passes overhead from the Ash Way Park and Ride Lot one mile north of Interstate 405. 07/19/23

I-5 converges with I-405/SR 525 south at Exit 182 in a half mile

Two lanes link I-5 south with Interstate 405 at Exit 182. Interstate 405 ostensibly provides a bypass of Seattle but instead comprises a crowded commuter route through Seattle’s eastern suburbs. 07/19/23

Exit 182 provides access only to I-405 south from I-5 south

Interstate 405 runs along the east side of Lake Washington from Bothel south to Renton. There is no access to SR 525 north from I-5 at Exit 182. 07/19/23

I-5 North at I-405 SR 525

I-5 north 1.5 miles ahead of I-405/SR 525 at Lynwood, Washington

I-5 advances 1.5 miles northeast from 44th Avenue W (SR 525 Spur) in Lynwood to the systems interchange (Exit 182) with SR 525 north and I-405 south. 07/20/23

I-5 north at SR 524, a half mile from I-405 in Lynnwood, WA

Exit 182 separates from Interstate 5 north in a half mile for SR 525 north to Mukilteo and I-405 south to Bothell and Kirkland. 07/20/23

I-5 continues north from SR 524 in Lynwood, WA to I-405/SR 525

The entrance ramp from SR 524 (196th Street SW) at Lynwood forms an auxiliary lane along I-5 north to Exit 182. 07/20/23

I-5 north at Alderwood Mall Pkwy and Exit 182 to I-405/SR 525

Alderwood Mall Parkway spans I-5 north by Alderwood Mall in Lynwood, just ahead of Exit 182 to I-405/SR 525. 07/20/23

Exit 182 separates from I-5 north for I-405 south and SR 525 north

Alderwood Mall Parkway spans I-5 north by Alderwood Mall in Lynwood, just ahead of Exit 182 to I-405/SR 525. 07/20/23

I-405 North End Throwback

I-405 North at I-5 SR 525

I-405 north one mile from I-5/SR 525 in 2006

Sign replacements made one mile from I-5 on I-405 removed the pull through panel for SR 525 north and added Everett for the exit to I-5 north. 08/29/06

I-405 north spans SR 524 just ahead of I-5 at Lynnwood, Washington

I-405 crosses SR 524 (Filbert Road) ahead of the lane drop for Interstate 5 north. 08/29/06

I-405 north at I-5 north to Everett, Washington in 2006

Interstate 405 north at the unnumbered exchange with I-5/SR 525. 08/29/06

I-5 South at I-405 SR 525

I-5 south at Interstate 405 south to Bothell, WA in 2006

Replaced overhead for Interstate 405 south on I-5 south at Exit 182 near Alderwood Manor. 08/30/06

I-5 south at Exit 183 and Martha Lake, Washington in 2006

Guide signs at Exit 183 were relocated from a sign bridge onto the overpass linking the HOV lanes with the Ash Way Park & Ride facility. 08/30/06

SR 525 South at I-5 I-405

SR 525 south at I-5/405 in 2006

The HOV lane for I-5 south was removed. Replacement of the I-405 pull through panel removed the HOV reference and Bellevue. 08/29/06

I-5 North at I-405 SR 525

I-5 north at 44th Ave W (SR 524 Spur), two miles from I-405/SR 525

Exit 181 A connects I-5 with 44th Avenue W to SR 524 in Lynwood just ahead of Alderwood Mall and two miles from I-405/SR 525. 08/30/06

I-5 north a half mile ahead of I-405/SR 525 in 2006

Replaced overhead assembly for I-405 south and SR 525 north posted a half mile ahead of Exit 182 on I-5 north. 08/29/06

I-5 north at I-405 south and SR 525 north in 2006

This overhead was replaced with bridge mounted signs at the Alderwood Mall Parkway overpass on northbound Interstate 5. 08/29/06

South End I-5 Washington 518 – Tukwila, Washington

I-405 South at I-5 SR 518

I-405 south enters Tukwila from Renton, WA, one mile from I-5/SR 518

Interstate 405 south concludes at a cloverstack interchange with I-5 and SR 518. 07/19/23

I-405 advances west from SR 181 and Christensen Rd to I-5/SR 518
I-405 arcs west between Tukwila Pkwy and Southcenter Blvd to I-5/SR 518

The ramp for I-5 north to Downtown Seattle includes access to adjacent Southcenter Boulevard and Westfield Southcenter mall. 07/19/23

61st Ave S spans I-405 at the HOV exit for I-5 north in Tukwila, WA

A left exit ramp links the south end of I-405 with the HOV lane along Interstate 5 north through Tukwila. 07/19/23

Ramps for I-5 and adjacent Southcenter Blvd depart I-405 south

A loop ramp connects I-405 with Interstate 5 south to Federal Way and Tacoma. SR 518 extends west along a freeway to SeaTac and Burien. 07/19/23

I-405 south ends at the ramp for I-5 south. SR 518 extends 3.40 miles west

A loop ramp connects I-405 with Interstate 5 south to Federal Way and Tacoma. SR 518 extends west along a freeway to SeaTac and Burien. 07/19/23

SR 518 East at I-5 I-405

Ramps from Airport Expwy tie into SR 518 one mile from I-5/405 at SeaTac, WA

International Boulevard (SR 99 south) spans SR 518 east at the exchange with Airport Expressway from Seattle-Tacoma International Airport (SEA), one mile from I-5/405 at Tukwika. 07/20/23

SR 518 east enters Tukwila, WA ahead of I-5 and I-405 north.

Leading east from Seattle-Tacoma International Airport (SEA) toward I-405, traffic on SR 518 increases to succeeding ramps for Southcenter Mall and Interstate 5. 07/20/23

SR 518 parallels the SoundTransit 1 Line east to I-5/405 in Tukwila, WA

Construction in 2008 added a third eastbound lane along SR 518 ahead of the ramps for Interstate 5. 07/20/23

SR 518 meets I-5/405 beyond the exit for 51st Ave S/Westfield Southcenter
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. 07/20/23

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. 07/20/23

I-5 North at I-405 SR 518

I-5 north at I-405/SR 518 - SeaTac, WA

Passing under South 178th Street, Interstate 5 advances one mile north to Exits 154A/B for SR 518 west and I-405 north. 06/24/15

I-5 north at I-405/SR 518 - Tukwila, WA

The ensuing exit along I-5 northbound links with parallel Southcenter Parkway at Westfield Southcenter mall. Exit 154 immediately follows for SR 518 and I-405. 06/24/15

I-5 north at I-405/SR 518 - Tukwila, WA

Passing under the Southcenter Parkway overpass in Tukwila, a lane drop occurs at Exit 154B for I-405 north to Renton. A high occupancy vehicle lane separates from the left while the I-5 northbound mainline continues with three lanes through the exchange. 06/24/15

I-5 north at I-405/SR 518 - Tukwila, WA

Traffic partitions along Exit 154 for I-405 north to Bellevue and SR 518 west to the SR 509 freeway at Burien. 06/24/15

I-5 South at I-405 SR 518

I-5 converges with SR 599, 1.5 miles from I-405 in Tukwila, WA

The southbound HOV lane along I-5 separates from the freeway mainline just ahead of the wye interchange with SR 599. The exchange (Exit 154 A) with Interstate 405 follows. 07/20/23

S 144th St spans I-5 one mile from I-405/SR 518 in Tukwila, Washington

Traffic from SR 599 south combines with I-5 just ahead of succeeding exits for Southcenter Boulevard, SR 518 west and Interstate 405 north. 07/20/23

I-5 south at SR 518 west and I-405 north in Tukwila, Washington

Exit 154 B departs from I-5 south next for SR 518 west to SeaTac and Burien. Left Exit 154 A joins the general travel lanes and the HOV lane with I-405 north to Renton. 07/20/23

I-5 south at at Left Exit 154 A for I-405 north to Renton, Washington

Left Exit 154 A joins the inside lanes of SR 518 east to Interstate 405 ahead of SR 181 (Valley Highway) south in Tukwila. 07/20/23

I-405 South End Throwback

I-405 South at I-5 SR 518

I-405 south at I-5/SR 518 - 2006

An end sign for Interstate 405 was formerly posted at the transition into SR 518 west. Photo by Chris Elbert (03/03/06).

I-5 South at I-405 SR 518

I-5 south one mile from I-405/SR 518 in 2006

Previous overheads for Exit 154 B to SR 518 west and Exit 154 A for I-405 north at the S 144th Street overpass in Tukwila. 08/29/06

I-5 south at Exit 154 B for SR 518 west in 2006

Exit 154 B departs for both Southcenter Boulevard and SR 518 west to Sea-Tac International Airport (SEA) and Burien just ahead of the left exits for Interstate 405 north to Renton. 08/29/06

I-5 south at Exit 154 A to I-405 north in 2006

Replaced overhead for Exit 154 A on I-5 south at Interstate 405 north. 08/29/06

Sources:

  1. Washington State Highway Commission letter to AASHO, dated July 14, 1958, retrieved from AASHTO Route Numbering Archive.
  2. Interstate 405 (Washington). AARoads Wiki.

Page updated February 1, 2024