Washington State Ferries is the largest ferry system in the United States, with ferries making more than 500 trips per day. The ferries are a tourist attraction, but also a necessity for the large proportion of the Kitsap workforce that commutes to Seattle-area jobs. Because West Sound is separated by water from the main economic corridor of Washington state, the entire transportation system — ferries, the highway grid, bridges and transit — are lifelines to economic as well as leisure pursuits. The completion of the second Tacoma Narrows span in 2007 eased the highway link from Kitsap to Interstate 5. Kitsap's mass transit system is focused on helping the community's Navy workers and personnel get to and from their workplaces.