Seattle is squeezed between Puget Sound and Lake Washington, and its highways have to cross water, hills and a ship canal to get anywhere. I-5 runs north and south through the middle of the city, over the Ship Canal Bridge and past downtown toward Tacoma and Everett. SR 99 tunnels beneath downtown and continues north as Aurora Avenue. I-90 and SR 520 cross Lake Washington on floating bridges to Mercer Island, Bellevue and Redmond, and I-405 carries Eastside traffic around the far side of the lake. The West Seattle Bridge is the main link to the peninsula across the Duwamish Waterway.
Those crossings are where the city's traffic stacks up. The I-5 corridor through downtown, the approaches to the 520 and I-90 bridges and the Mercer Street area near South Lake Union back up most weekdays, and a car that stalls on a floating bridge has nowhere to go. For a mobile mechanic, the bigger daily challenge is parking: many neighborhoods rely on street spaces and zoned permits, apartment garages are tight, and some of the steepest streets in the country run through Queen Anne, Capitol Hill and the hills above the lake. A safe, level spot is often the first thing to sort out.
Sea-Tac Airport sits south of the city, and its garages are common service locations for cars that sat during a trip. Link light rail runs from the airport through downtown, Capitol Hill and the University District to Northgate and beyond, and King County Metro buses fill in the rest. Washington State Ferries leave from the downtown waterfront and from Fauntleroy in West Seattle. The University of Washington, its medical center and the hospitals on First Hill draw thousands of commuters every day.