CDM Constructors, Inc.

Client:

Tim Boesch - Project Manager

Scope Of Work

Seattle's old State Route (SR) 520 floating bridge, once vulnerable and limited in capacity, was given renewed vitality with the help of toll financing.

Built in the 1960s, Seattle's old SR 520 floating bridge spanned Lake Washington to connect Seattle to its eastern suburbs and Microsoft’s headquarters. In time, it had become vulnerable to windstorms and earthquakes, had limited capacity and no access for pedestrians and bicyclists. The Washington State Department of Transportation (WSDOT) wanted to replace the bridge to help ensure safety and expand and improve access for more vehicles and modes. Funding the $4.56 billion full-corridor project, however, was a big challenge. WSDOT found a portion of the solution through toll financing.

In 2009, WSDOT hired CDM Smith to perform an investment grade traffic and revenue study to forecast traffic volumes and revenue for pre-completion—when the existing bridge would be tolled—as well as post-completion—when tolls would transfer to the replacement bridge through 2056, the expected bond duration. CDM Smith’s study was completed in August 2011, the first bonds were sold in October, and the all-electronic tolling facility, featuring time-of-day and day-of-week variable tolling, opened before year’s end. The new 1.44-mile replacement SR 520 Bridge—the longest floating bridge in the world—opened to traffic in April 2016.