Highway 99 at South Lake Union will close much of this weekend, except when drivers need travel lanes to reach Seattle Mariners games against the Oakland Athletics.
The closures affect the Battery Street Tunnel, as well as Aurora Avenue North from Valley Street to Denny Way — which means northbound traffic on the Alaskan Way Viaduct must exit at mid-downtown or at Western Avenue.
Seattle City Light is moving electrical lines and poles for the city’s Mercer West street project, while crews for the Washington State Department of Transportation will install a water main under Aurora near Harrison Street.