Seattle Transport:

As with almost every other city in western North America, transportation in Seattle is dominated by automobiles, although Seattle is just old enough that the city's layout reflects the age when railways and streetcars (known locally as "trolleys") dominated. These older modes of transportation made for a relatively well-defined downtown and strong neighborhoods at the end of several former streetcar lines, most of them now bus lines.
Because of the isthmus-like geography of Seattle and the concentration of jobs within the city, much of the transportation movement in the Seattle metropolitan area is through the city proper. North-south transportation is highly dependent on Interstate 5 corridor, which connects the Puget Sound area with southwest Washington cities, the Portland metropolitan area, and cities to the north such as Bellingham. I-5 continues as British Columbia Highway 99 at the US-Canada border's Peace Arch crossing, between Blaine and Surrey. State Route 99 is also a major arterial in the western half of the city and includes the Alaskan Way Viaduct along the Seattle waterfront. Because of seismic instability, there are plans to replace the viaduct. Transportation to and from the east is via State Route 520's Evergreen Point Floating Bridge and Interstate 90's Lacey V. Murrow Memorial Bridge and Third Lake Washington Bridge, all over Lake Washington. Those bridges are the first, second, and fifth longest floating bridges in the world, respectively. State Route 522 connects Seattle to its northeastern suburbs.
Unlike most North American cities, water transportation remains important. Washington State Ferries, the largest ferry system in the United States and the third largest in the world, operates a passenger-only ferry from Colman Dock in Downtown to Vashon Island, car ferries from Colman Dock to Bainbridge Island and to Bremerton, and a car ferry from West Seattle to Vashon Island to Southworth. Seattle was once home to the Kalakala, a streamlined art deco-style ferry that plied the waters from the 1930s to the 1960s. The ship has since fallen into disrepair.
Seattle contains most of Boeing Field, officially called King County International Airport, but most of the city's airline passengers use Seattle-Tacoma International Airport in the city of SeaTac. Seattle is also served by three Amtrak routes at King Street Station: the Cascades, the Coast Starlight, and the Empire Builder.