The car-sharing market in Seattle has been the fastest growing in the U.S. since December of 2012, when Daimler's car2go North America set up shop in the city, according to Daimler.

Since late 2012, more than 40,000 drivers have registered for the company's point-to-point car-sharing service to use a network of 500 smart fortwo subcompact cars.

In the past year, 170 new cars have been added to the initial fleet of 330 vehicles. The car-sharing area was expanded in April to 52 square miles from 42 square miles. to incorporate Mount Baker, Columbia City and portions of Georgetown and West Seattle. Designated car2go parking spaces were recently added to Fauntleroy Ferry Terminal parking.

Other U.S. car2go locations include Austin, Texas; San Diego; Washington D.C.; Portland, Ore.; Miami; Denver; Minneapolis, Minn.; and Columbus, Ohio.