I-405 Corridor Program

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How will we address long-term solutions for I-405?
I-405 is one of the state's most congested corridors. Starting more than a decade ago, WSDOT worked with cities, counties, federal agencies, transit agencies and community groups to develop consensus on a long-term vision for the multimodal redevelopment of this highway. 

This effort culminated in a three-year environmental impact statement (EIS) development process that outlines transit, roadway and environmental investments. The EIS, approved with the Record of Decision in October 2002, now serves as the corridor Master Plan. WSDOT continues to work with local communities and transit agencies to improve I-405 with available funding. 

What has the I-405 Corridor Program accomplished to date?
Since the master plan for I-405 improvements was adopted, we have focused on funding groups of projects that directly address the worst congestion chokepoints first, coordinating all transportation modes into a working system. With funding from the 2003 Nickel and 2005 Transportation Partnership Account, the state has already invested nearly $1.5 billion into the corridor, including completed projects in Bellevue, Bothell, Kirkland and Renton. 

The 2015 Connecting Washington transportation package passed by the Legislature included $1.3 billion of new investments in the corridor. The I-405/SR 167 Direct Connector  began construction in fall 2016. The Renton to Bellevue Widening and Express Toll Lanes project is currently in the environmental review phase, with construction expected to begin in 2019. 

WSDOT also received approval in summer 2016 to construct a new northbound peak-use shoulder lane on I-405 between SR 527 and I-5. This project, which is opened to traffic in April 2017, represents the first reinvestment of I-405 express toll lane revenue back into the corridor. Longer-term plans include two additional lanes in each direction of I-405 between SR 522 and I-5 in Lynnwood. 

The End Result: An Improved Multimodal System
The I-405 Master Plan is a balanced, multimodal plan to guide future transportation investments. Highlights include:

  • Two new lanes in each direction
  • Local arterial improvements
  • 10 new transit centers
  • Bus rapid transit (BRT) system
  • 50 percent transit service increase
  • Direct access ramps for transit and carpools
  • 5,000 new Park and Ride spaces
  • 1,700 new vanpools
  • Bicycle and pedestrian improvements
  • Potential managed lanes system
  • Environmental enhancements, including stormwater and habitat improvements