The state Department of Transportation plans to close the right lane of the southbound Alaskan Way Viaduct, as well as the South Atlantic Street offramp, from 7 a.m. to 5 p.m. Saturday.
A similar but unannounced closure last Saturday caused early-afternoon traffic backups all the way to the Battery Street Tunnel, wasting about 20 minutes for any drivers stuck in the slowdown. The 5 p.m. reopening will provide two hours of normal flow before the 7 p.m. Sounders FC match against San Jose.
Construction crews are preparing for a lane shift later this year. The temporary Highway 99 curves next to CenturyLink Field will be moved to make room for construction of the permanent Highway 99 tunnel-approach lanes, shown in green below.
In addition, the intersection of Fifth Avenue North and Mercer Street will completely close for paving and excavation from 11:30 p.m. tonight until 5 a.m. Monday. The Seattle Department of Transportation is building a two-way Mercer underpass beneath Highway 99.