The Seattle Department of Transportation noted today that a major milestone has been reached in the Spokane Street Viaduct widening project which will nearly double its width by adding 41 feet of new roadway.

Westbound traffic on the Spokane Street Viaduct will be shifted onto the newly constructed bridge deck tomorrow morning, December 23, in advance of the morning commute.

The SDOT press release states:

Motorists will find the shift to be seamless, maintaining the current two lanes of traffic in each direction; however, the posted travel speed for westbound traffic will be temporarily reduced to 25 miles per hour (down from 35 miles per hour) until the project is completed this coming summer. The remaining construction work requires westbound travel lanes to be narrower than standard lane widths. This, in addition to the presence of construction vehicles entering and exiting travel lanes, requires a lower travel speed for driver safety.

Following this initial traffic shift, the contractor will connect the old and new structures, construct a new center median between the old and new structures, and install new lighting in the median. Over the next few months, eastbound traffic will be shifted from the south side to the north side of the old structure so that the contractor can begin demolition of the existing south barrier. This spring, eastbound traffic will be temporarily moved over to the new viaduct so that the old bridge deck can be repaired and repaved. At that point, eastbound traffic wishing to exit to SODO will still be able to do so, using either the First Avenue S off-ramp or the Fourth Avenue S loop ramp exit.

For additional information, please see SDOT’s project Web site, http://www.seattle.gov/transportation/spokanestreet.htm