King County Metro has the most aggressive public-transit strategy, bringing 30 extra buses on duty to reduce wait times and carry overflow passengers. An Oct. 1 service change increased midday trips on West Seattle's workhorse Route 54.

Planners devised a clever strategy to get commuters downtown in the morning: Buses that normally take the Viaduct will exit their bus lane at First Avenue South to lightly used lower Spokane Street, then be waved by a traffic cop to a bus-only left turn at Fourth Avenue South. That road has plenty of room. But if it gets clogged, riders can get off and walk a block and a half to meet Link light rail at Sodo Station, to the downtown transit tunnel.

Buses that normally run on First Avenue South through Sodo will take their normal routes, up First to Starbucks Center, then turn east on South Lander Street to enter downtown via Fourth Avenue South.

Seattle just added a morning bus lane on Avalon Way Southwest in West Seattle, but it covers only a few blocks, so buses might still be snared farther uphill. There will be free 19-seat shuttle buses to take West Seattle residents to and from the water taxi: the 773 will come from the Avalon and Junction areas; the 775 will come from the Admiral and Alki areas.

It's in the evening when Metro is defenseless. Lacking a Viaduct junction to the high West Seattle Bridge, those buses will wend through Sodo to the lower swing bridge. The Coast Guard agreed to avoid nearly all maritime openings from 3 p.m. to 6 p.m., but train crossings by BNSF Railway and heavy truck traffic to the Port of Seattle are likely. Four cargo ships are coming in Sunday, and three more are coming in Wednesday.

Northsiders can expect delays because the Battery Street Tunnel will close and cause congestion on Aurora Avenue North, including Route 358, and because some lines serving Greenwood, Shoreline and Ballard use buses arriving from West Seattle, which will take longer to reach the north.

In case of severe Interstate 5 congestion heading south, it might be a good idea to use the Mountlake Terrace park-and-ride garage and take a bus. North Seattle lots at the Northgate Transit Center already are at or near full.

Mike Lindblom: 206-515-5631 or mlindblom@seattletimes.com