After some three years of construction, the Spokane Street Viaduct Widening Project is nearing completion. The long-awaited westbound consolidated on/off-ramp at First Avenue S opened to traffic on August 31 (see photo below), ending the need for those traveling from SODO to West Seattle to detour over the surface Spokane Street Swing Bridge.
The largest remaining project element still impacting motorists has been the closure of the eastbound off-ramp at First Avenue while it is repaired and resurfaced. The off-ramp is now scheduled to reopen Wednesday, September 19.
Substantial completion of the entire project is expected in early October, with its final cost coming in below the initial project estimate of $168 million.
The project has doubled the viaduct width, adding some 41 feet with a new structure built immediately adjacent to the old structure, which was refurbished and seismically reinforced. The seismic work included the installation of “earthquake drains” under Fourth Avenue.
With substantial financial support from the Washington State Department of Transportation (WSDOT), a previously nonexistent eastbound off-ramp at Fourth Avenue was added and opened to traffic in the summer of 2010 (see photo below). 
Wider lanes and the addition of shoulders, along with deceleration and merge lanes, result in a significant improvement in traffic flow. Finally, lower Spokane Street has new pavement, sidewalks and utilities, as well as a bicycle/pedestrian pathway on the north side of the street.
To get the very latest updates on final completion of the entire project, visit: http://www.seattle.gov/transportation/spokanestreet.htm