with public transit is 7 km, while 12% travel for over 12 km in a single direction. Aviation Boston's principal airport is Logan International Airport (BOS), situated in East Boston just across inner Boston Harbor from downtown Boston. Logan Airport is operated by Massport and has extensive domestic and international airline service. Logan Airport is linked to downtown by several highway tunnels. The Silver Line bus rapid transit uses these to connect Logan air terminals with South Station. There are also shuttle buses between the terminals and the Blue Line Airport station. To help address overcrowding at Logan Airport, Massport operates two other airports in eastern Massachusetts: L.G. Hanscom Field Worcester Regional Airport: formerly owned by the city of Worcester until ownership transfer to Massport was mandated by law in 2009, and subsequently completed on June 22, 2010. In addition, MassPort has designated two out of state regional airports (which are administered independently) as reliever airports: T. F. Green Airport in Providence, Rhode Island Manchester-Boston Regional Airport in Manchester, New Hampshire Around 2010, the MBTA commuter rail initiated new train service from T.F. Green Airport to Boston. There are also several general aviation facilities for private planes in the Boston area, including Hanscom Field, Norwood Memorial Airport and Beverly Municipal Airport. Since the September 11, 2001 attacks, strict security has been implemented at all of Boston's airports. Because of this and its location as the closest American port to Europe, Boston is an emergency destination for airliners that experience security or mechanical problems while en route to the US, although they may also be diverted to Halifax (Nova Scotia), or other Canadian airports. Boston Vision Zero Plan In 2015, mayor Marty Walsh announced that the city of Boston would become part of a worldwide program known as Vision Zero. Vision Zero is a plan self described as “a new standard for safety on our streets.” The plan aims to eliminate deaths caused by transportation, whether that be pedestrians, personal vehicle riders, or cyclists. Since 2015, the city of Boston has adopted several different policies aimed to help bring down the number of fatalities caused by Transportation in Boston. These policies include the creation of a 25-mile per hour speed limit law citywide, and the implementation of Neighborhood Slow Streets, a tool of Traffic calming designed to make personal vehicles slow down in residential areas. Pedestrian deaths have fallen to 57