South Downtown I-405 Access Study

Header Image
I-405 corridor in Bellevue

Bellevue continues to grow, with the new East Main light rail station opening in 2023, plans to further develop south downtown Bellevue and expanded toll lanes on Interstate 405 (I-405) opening in 2024. To minimize traffic congestion and help people get where they need to go, whether walking, biking, riding transit or driving, the city and the state Department of Transportation partnered to study  options, including a new interchange, to access I-405 in south downtown Bellevue.

Final Report

Following a year of analysis and public engagement, in July 2021 the South Downtown I-405 Access Study confirmed the need for additional access to/from south Downtown and I-405. The City Council unanimously supports the recommendation to advance the Lake Hills Connector southbound on-ramp to I-405 as the alternative that best meets the city's transportation needs in the south Downtown area. 


Vicinity map of the South Downtown I-405 Access Study
Access Study Vicinity Map. Click image to enlarge

The I-405 Master Plan envisions a new interchange in Bellevue, south of Northeast Fourth Street. The South Downtown I-405 Access Study evaluated various improvement options that would be meet Bellevue’s transportation needs.

Proposed development along 114th Avenue Southeast, near the East Main light rail station and within the Wilburton area has created a pressing need to identify an alternative(s) preferred by the City to meet the transportation needs for the South Downtown area and to provide the recommended alternative(s) to WSDOT. Identifying an alternative will also enable the city to communicate to property owners and developers about right-of-way needs and site access options.

The I-405 Access Study will inform WSDOT’s future environmental review and freeway access revision request processes in connection with WSDOT’s I-405 proposal, which will be initiated when funding is available.

This study builds upon WSDOT’s 2015 analysis where they evaluated eight potential access options at several locations between Northeast Second Street and Southeast Eighth Street.

For additional project history and background, read the overview

City Council identifies alternative 

Following a year of study and public engagement, the City Council unanimously supported the recommendation to advance a Lake Hills Connector southbound on-ramp to I-405 as the alternative that best meets the evaluation criteria and the goals of the study. 

Lake Hills Connector Alternative Map I-405 Access Study

The Lake Hills Connector southbound on-ramp concept adds vehicle access to I-405 southbound with minimum property and environmental impacts at a reasonable cost (estimated at $150 million in 2030 dollars) compared to the other alternatives. It also aligns with city land use and urban design policies and allows the East Main Transit-Oriented Development (TOD) land use code amendment process to continue.

The State Legislature has the ultimate decision-making authority to fund the project. The final project design, environmental analysis and construction would be carried out by WSDOT in accordance with federal highway and transportation approval processes.

In a related discussion, councilmembers urged the Transportation Department to accelerate a separate project that would provide pedestrian and bicycle access along Southeast Eighth Street to compliment the Lake Hills Connector alternative.

Input was provided by stakeholders who represent properties and neighborhoods within the study area, business and transportation interest groups and the community at large.

Five conceptual options were evaluated for consistency with city policies, travel time reduction, access, safety, cost and property and economic development impacts.

  • Lake Hills Connector southbound on-ramp
  • Southeast Sixth Street extension and southbound on-ramp
  • Southeast Sixth Street extension with inside access 
  • Northeast Second Street extension 
  • No building (No new interchange)

Study materials


The study schedule for the I-405 access study