information from SDOT
 
This weekend the speed limit on the Spokane Street Viaduct is increasing to 40 miles per hour (mph) between I-5 and First Avenue South. While the speed limit was 35 mph based on the structure’s original design, the Spokane Street Viaduct Project widened the roadway, which allows for a 40 mph speed. The project officially concluded last December, but the lower speed limit remained in place while the Seattle Department of Transportation (SDOT) monitored operations. SDOT has concluded the Spokane Street Viaduct is functioning well and that the speed limit can be safely increased.
 
Last weekend SDOT replaced aging and worn overhead signs on the structure. The new signs are made of a reflective material that works so well the electric lighting associated with overhead signs is not needed. The Washington State Department of Transportation currently uses this material and we are taking this opportunity to review its use in Seattle.
 
The Spokane Street Viaduct Project doubled the viaduct’s width, and refurbished and seismically reinforced the older portion. The additional width allowed for wider travel lanes, shoulders and deceleration and merge lanes to be installed. The project also added a new eastbound off-ramp at Fourth Avenue S and fully reconstructed the lower S Spokane Street in concrete, including a sidewalk on the south side and multi-use trail on the north side. Finally, artwork was added to enliven the area below the viaduct with color and images that recollect the natural and cultural history of the location.