Boston is one of the few major U.S. cities where a significant portion of the population relies on something other than a private car. While driving remains common for those commuting from the suburbs, "Bostonians" themselves have the highest walking rate of any major American city. The city's compact, historic layout makes it exceptionally pedestrian-friendly. For longer distances, most people use the Massachusetts Bay Transportation Authority (MBTA), locally known as "The T." This system includes the nation's oldest subway lines (Red, Orange, Blue, and Green), an extensive bus network, and a commuter rail that fans out across eastern Massachusetts. Additionally, cycling has exploded in popularity, supported by the Bluebikes bike-share program and an expanding network of bike lanes. During the summer, water taxis and ferries provide a scenic alternative for those traveling across the harbor to East Boston or the Seaport. Overall, the "average" traveler in Boston likely uses a combination of the subway and their own two feet to navigate the "Hub."