I-405 Corridor Program

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What is the long-term plan for I-405?
Interstate 405 is one of the state's most congested corridors. Starting more than a decade ago, WSDOT has 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 a balanced approach to transportation, including a blend of transit, roadway, non-motorized and environmental investments. The EIS, approved with the Record of Decision in October 2002, now serves as the corridor Master Plan.

Major features of the Master Plan include two new lanes in each direction, a managed lanes system, local street improvements, transit improvements (including a new Bus Rapid Transit system), and bicycle and pedestrian improvements. 

WSDOT continues to work with local communities and transit agencies through our I-405/SR 167 Corridor Executive Advisory Group to improve I-405 within 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 building groups of projects that directly address the worst congestion chokepoints first, coordinating all transportation modes into a working system.

WSDOT has now delivered all 15 construction projects for the I-405/SR 167 corridor funded by the 2003 Nickel and 2005 Transportation Partnership Account, with nearly $1.5 billion in investments in Bellevue, Bothell, Kirkland and Renton--all on time and on budget.

Most recent highlights include the SR 167 HOT lane extension and the I-405 Bellevue to Lynnwood Widening and Express Toll Lanes project. In April 2017, WSDOT opened a new northbound peak-use shoulder lane on I-405 between SR 527 and I-5, which represents the first reinvestment of I-405 express toll lane revenue back into the corridor.

What are our next steps for the I-405 corridor? 
In 2015, the Legislature funded about $1.3 billion of new investments in the corridor through the Connecting Washington package. Several of these projects are well under way, including: 

WSDOT is also partnering with Sound Transit to deliver the new I-405 Bus Rapid Transit system, with a scheduled opening date of 2024. I-405 BRT is a new high-capacity transit service providing fast, frequent and reliable bus connections along I-405 and SR 518 from Lynnwood to Burien with a new transit center in South Renton and 11 BRT stations, three of which will include added parking. Buses will travel primarily in the managed lanes to increase speed and reliability.