FAQs

The I-405 corridor program Master Plan approved in 2002 includes a new half-diamond interchange in Bellevue to improve access to/from the south. The city and WSDOT are studying, developing, and evaluating interchange location(s) and configuration(s) to improve access to I-405 and make it easier for people to walk, bike, ride transit, or drive around the city.  This study supports economic development and livability in and around downtown Bellevue. This is an important step toward implementing the I-405 Master Plan. 

Recent proposed development activities along 114th Avenue Southeast, the East Main Station and the Wilburton areas have created a pressing need for the city to identify a preferred connection alternative. Not knowing the specific location and configuration is leaving the future of 114th Avenue Northeast in a state of uncertainty, with impacts on active development and the East Main transit-oriented development. Selecting a preferred option, which could be one or a combination of two or more of the remaining options, will position WSDOT for possible state funding for design and construction. 

• Consistency with Bellevue policies and plans;
• Consistency with Washington State Department of Transportation (WSDOT) and Federal Highway Administration (FHWA) policies including the I-405 Master Plan; and,
• Constructability.

1. Northeast Second Street/Northeast Fourth Street One-Way Couplet
2. Southbound on-ramp and northbound overpass at Northeast Second Street
3. Northeast Second Street extension to Wilburton
4. Half diamond interchange at Northeast Second Street with an extension east
5. Extended Northeast Second Street with westbound to southbound on-ramp
6. Half diamond interchange at Main Street
7. Southeast First Street overcrossing to 116th Avenue Northeast with a southbound on-ramp
8. Southeast Fifth Street overcrossing to 116th Avenue Northeast with a southbound on-ramp
9. Southeast Sixth Street extension with express toll lane access to and from south
10. Southeast Sixth Street overpass to 116th Avenue Northeast with southbound on-ramp
11. Lake Hills Connector southbound on-ramp (close westbound to southbound on-ramp at Northeast Fourth Street)
12. Southbound ramp to Express Toll Lane with braided ramp outside of Southeast Eighth Street
13. No build (no new interchange)

• Alignment with adopted plans and policies: Consistency with existing plans and policies including transportation, land use, urban design and environmental stewardship
• Travel time: Travel time savings, and traffic operations on city roads and on I-405
• Access and safety: Access to I-405, connection between Downtown and Wilburton areas, and ease of access for people walking or biking
• Impact on property development: Complete and partial property acquisition to build the project, property access restrictions and impact on future economic development
• Cost: Acquiring right-of-way, construction, mitigating wetlands/streams, relocating utilities, removing fish barriers and restoring stream connections

1. Lake Hills Connector southbound on-ramp. This alternative would construct a southbound on-ramp from Lake Hills Connector to southbound I-405. It would complement the existing I-405 northbound off-ramp to Lake Hills Connector. It restricts westbound to southbound I-405 on-ramp movement on Northeast Fourth Street bridge to reduce westbound back up on the bridge.
2. Southeast Sixth Street extension and southbound on-ramp. This alternative would elevate and extend Southeast Sixth Street over 114th Avenue and I-405 to Lake Hills Connector/116th Avenue and construct on-ramp to I-405 southbound. This new ramp would pair with the existing I-405 northbound off-ramp to Lake Hills Connector to form a half-diamond interchange. This alternative includes bike lanes and sidewalks on the new east-west connection.
3.  Southeast Sixth Street extension inside access. This alternative would elevate and extend Southeast Sixth Street over 114th Avenue and I-405 to 116th Avenue and construct direct I-405 express toll lane access ramps to and from the south. This alternative includes bike lanes and sidewalks on the new east-west connection.
4. Northeast Second Street extension. This alternative would extend Northeast Second Street to 116th Avenue without ramp connections to I-405. It could go either south or north of the Hampton Inn. This alternative includes bike lanes and sidewalks on the new east-west connection.
5. No build (no new interchange)

• Northeast Second Street/Northeast Fourth Street One-Way Couplet
• Southbound on-ramp and northbound overpass at NE Second Street
• Half diamond interchange at Northeast Second Street with an extension east
• Half diamond interchange at Main Street
• Extended Northeast Second Street with westbound to southbound on-ramp
• Southeast First Street overcrossing to 116th Avenue Northeast with a southbound on-ramp
• Southeast Fifth Street overcrossing to 116th Avenue Northeast with a southbound on-ramp
• Southbound ramp to Express Toll Lane with braided ramp outside of Southeast Eighth Street

Following this round of community engagement, the study team is expected to present the analysis findings along with stakeholder and public input to the council in April 2021 for its consideration in selecting a preferred alternative.  To receive council agendas, subscribe here.

Currently there is no funding for construction. The state legislature has the ultimate authority to allocate funding for final design, environmental documentation, right-of-way acquisition, and construction.

Some key themes we heard from the first online open house were:

• Support improving access to downtown Bellevue and Wilburton.
• Support more capacity for vehicle traffic and reducing congestion.
• Prioritize transportation improvements and access for people walking, biking and riding transit.
• Maintain access for people walking, biking and riding transit.
• Provide an east-west connection over I-405 without access to I-405.
• Consider combining alternative features.
• Coordinate the new interchange with other city initiatives, including the Grand Connection.
• Concern that a new interchange may encourage vehicle traffic, or “induce demand”, contribute to climate change and does not align with the city’s environmental stewardship goals.
• Concern about the cost of building a new interchange.
• Concern about impact to traffic on local streets with some alternatives.
• Concern about impacts to planned Transit-Oriented Development (TOD).
• A new interchange may not help improve access to I-405 until the city and WSDOT address congestion on I-405.
• An additional I-405 access is unnecessary, especially with current investment in alternative modes of traffic (Sound Transit light rail expansion, bicycle routes, walking and transit).

"Daily person hours" is modeled travel time savings for all travelers within the City of Bellevue on an average weekday. The “daily person hours” of savings is calculated by multiplying total daily vehicle travel time savings by an average vehicle occupancy factor of 1.35, as predicted by the City's travel demand forecast model.

A half-diamond interchange is an interchange with only two diagonal ramps on and off from one side of the roadway. This interchange serves traffic to and from one direction along the freeway only. Two examples of a half-diamond interchange include State Route 520 and Lake Washington Boulevard (Bellevue) and Interstate 405 at Northeast 116^th Street (Kirkland).