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SR 99 - S. Holgate Street to S. King Street Viaduct Replacement - Keeping people and goods moving

As we work to replace the Alaskan Way Viaduct between S. Holgate and S. King streets, we remain conscious of the effects that construction has on drivers, movement of goods, and on those who live and work near the project.

WSDOT and our project partners developed a comprehensive plan to help keep people and goods moving during construction to replace the Alaskan Way Viaduct. Our plan builds upon and complements existing projects and services, and helps fund new projects. The plan includes:

Improvement projects

Our transportation system is a network. When congestion occurs on SR 99 it can have a ripple effect on nearby routes. If northbound SR 99 is bumper to bumper, drivers move to other routes into Downtown, such as I-5 and Fourth Avenue S. and soon those roads can become congested as well. 

We recognized the interdependence of the transportation system and helped fund the following projects that improve alternate routes and help the roads we already have operate more efficiently.

Arterial streets traffic and transit flow upgrades

The City of Seattle, with funding assistance from the Alaskan Way Viaduct Program, is completing upgrades that will provide driver information and keep traffic moving in the Denny Way, Elliott Avenue/15th Avenue W., SODO and West Seattle corridors. These upgrades include:

  • New signal timing equipment that responds better to changes in traffic volumes and helps move traffic through busy intersections.
  • New overhead message signs that tell drivers about incidents and backups ahead.
  • New technology to provide travel time information to drivers so they can make informed choices about their route before they get in their vehicle.

Improved transit service

Increasing transit options helps keep people and goods moving by giving people travel options and reducing the vehicle demand on SR 99 and other routes into and out of downtown Seattle. WSDOT worked with King County to provide additional transit service to accommodate 1,212 new riders on five bus routes (21, 22, 54, 56, and 121) that serve areas where construction will have an impact.

Visit Metro Online and enter the route number in the box get timetables, maps and travel alerts for each route. 

Trip reduction programs

WSDOT is investing $1.7 million and King County Metro is providing more than $1 million for trip reduction programs. Using extensive research we strategically funded enhancements to existing trip reduction programs. These enhancements will remove trips from SR 99 and key alternate routes during construction.

We will implement most of these program enhancements in early 2011, just as construction and closures starts to get more intense. But you don’t have to wait until then to learn about existing tools and commute options. Find out how you can reinvent your commute now.  

Public information and outreach

Giving travelers timely and accurate information about upcoming construction closures is one of the most effective ways to keep people and goods moving. When travelers are aware of route restrictions in advance, they have to time to plan to take other routes, avoid trips, use transit or carpool. This helps free up space on the roads for those who don't have these options.

Throughout the course of the project we will continually update the public about closures and other construction effects using a variety of tools ranging from old fashioned face-to-face contact and the latest high-tech tools.  Some of these include:


Coordination with other agencies and projects

The SODO and Pioneer Square neighborhoods will be construction hot spots for several years with work on WSDOT, Seattle Department of Transportation, and private developer projects occurring at the same time. Add utility work into the mix and the presence of two major stadiums, an event center, the Port of Seattle, private development projects and you can see why coordination among all these entities is not just desirable, but essential.
We are facing this challenge by meeting weekly with local stakeholders, representatives from other construction projects, and staff from City of Seattle departments and the Port of Seattle. We review proposed closures and scheduled events, gather feedback and determine how we can best get the work done while minimizing traffic and other disruptions.