Bridges supporting mobility & connectivity through three east King County interchanges

Problem

Our region’s glacial topography – including features such as Puget Sound, our lakes and hills – serve as the bedrock that supports our region’s quality of life. But these beautiful natural features create bottlenecks and choke points in our transportation network, and combined with record-breaking population growth, often slow transportation to a glacial pace.

Parallel with our sometimes-glacial I-405 corridor, a regional trail is under development to provide safe travel for large numbers of commuters and travelers interested to bike or walk to work and who will soon be drawn to multi-modal transit centers connecting the region with light rail. But the trail has its own choke points with complicated and potentially dangerous road crossings that slow travel for multiple modes.  Eliminating bottlenecks requires funding for a solution that allows flow and safe travel for non-motorized and motorized mobility.

Solution

This proposal seeks relief by building bridges at three key interchanges along the trail and road system, building up-and-over busy streets and enabling unimpeded flow for motor vehicles and muscle-powered vehicles alike. Keeping them separated ensures safety and ensuring safety will increase trail use; increased trail use will reduce motorized traffic and help avoid conflicts between modes, and increase flow that's expected to radiate out from this busy corridor across our larger region. This grant will ensure this work gets done faster than a glacial pace.

Application materials

• Narrative 11.8 MB
• Letters of support
• 2018 King County BUILD Application Benefit-Cost Analysis Appendix 359 KB
• Benefit-Cost Analysis Appendix tables 35 KB
• Benefit-Cost Analysis Calculation Workbook 972 KB
   
• Supplemental information