The SR 520 Bridge Replacement and HOV Program is moving forward, in phases, with construction of the remaining improvements to SR 520 in Seattle – what we call the “Rest of the West.” The SR 520/I-5 Express Lanes Connection Project is one of the major stages of the highway's west side reconstruction. This project will create a dedicated, reversible transit and carpool connection between SR 520 and the I-5 express lanes, along with a reversible transit/carpool ramp at the I-5/Mercer Street interchange. This brief video shows how this new connection will work.
Project news
- Construction is planned to begin later this summer on this new, reversible bus and carpool connection between SR 520 and I-5's Mercer Street interchange. You can learn more from this July blog article and video.
- WSDOT announced in May that Walsh Construction submitted the lowest bid for building this project. You can read more about the announcement in this news release.
- WSDOT held a virtual meeting for contractors in March regarding contracting opportunities with two design-bid-build projects: the SR 520/I-5 Express Lanes Connection Project and the Alaskan Way Viaduct South Access Surface Street Connections Project. The meeting was for interested contractors of all sizes, from large primes to smaller minority-, veteran-, and women-owned businesses. Construction for both projects begins in summer 2021. If you have questions, contact Regina Glenn, WSDOT Megaprograms Diversity and Inclusion Manager at GlennRe@consultant.wsdot.wa.gov.
- The city of Seattle granted WSDOT a project-long nighttime noise variance for the SR 520/I-5 Project so that crews can do some of the work at night to avoid weekday traffic disruptions and enable a safer work zone. Visit the Seattle Services Portal, project number 6733975-NV, for information on the noise variance and to view WSDOT’s application. Also, you can read this Q&A on our Major Public Projects Construction Noise Variance (PDF 228KB) to learn more.
Needs & Benefits
Seattle has experienced a population and employment boom, especially in the South Lake Union neighborhood. At the same time, the Eastside’s technology-driven cities continue to experience rapid growth. The region’s growth underscores the importance of a safe, reliable transit/HOV link between Seattle and the Eastside via SR 520. This project will extend SR 520’s new transit/HOV system onto the I-5 express lanes, creating a direct bus and carpool connection between SR 520, South Lake Union and downtown Seattle.
The end result
- A new, reversible transit/HOV ramp between SR 520 and the I-5 express lanes
- Restriped I-5 express lanes that retain the four existing lanes while adding a reversible transit/HOV lane between the I-5 / SR 520 interchange and Mercer Street
- A modified, reversible ramp between the I-5 express lanes and Mercer Street
Project benefits
- Safer, more reliable travel between the Eastside’s growing cities and Seattle’s booming South Lake Union neighborhood from a new, reversible transit/HOV lane connecting SR 520 and Seattle’s I-5 / Mercer Street interchange
- Earlier-than-planned Eastside / South Lake Union transit service via the reversible I-5 express lanes connection; the connection could open as early as 2023 or 2024 for transit instead of the originally expected opening in 2029
- A more efficient phasing of SR 520 construction that minimizes contractor overlap in the Montlake area while keeping regional and local traffic moving during construction
Timeline
- Summer 2021: estimated start of construction
- Estimated construction duration: 3 years*
* The reversible transit/HOV lane initially will open only to transit; carpools will use the reversible lane following completion of a new Portage Bay Bridge and Roanoke lid.
Funding
This project is part of the remaining $1.6 billion in SR 520 improvements from Lake Washington to I-5 – the “Rest of the West.” These improvements are funded by the 2015 Connecting Washington transportation legislation. For more information on SR 520 funding, visit the Budget and Performance page.
