Washington State Department of Transportation (WSDOT) received five contactor proposals for the project. Of those, Flatiron West Inc. submitted the lowest bid of US$199.5 million, which is below the WSDOT engineer’s estimate. 

“The new SR 520 floating bridge will be the world’s longest floating bridge, but it actually ends more than a mile from shore,” said WSDOT SR 520 program administrator Julie Meredith. “The new approach bridge will serve as a vital connection between the new floating bridge and the commerce centres of Seattle.”

Unlike the new floating bridge, the West Approach Bridge North will be supported by solid columns fastened directly to the bottom of Lake Washington.