The journey from the USA can be crossed within five hours from east to west and within two hours from north to south. Strong competition between airlines has resulted in a wide variation in airfares. Driving is a wonderful way to see the USA but distances can be huge. Nonetheless, for those visitors with sufficient time, travelling by road is an idyllic way to get a sense of both the enormity and the diversity of the country. Besides, road tripping is a much-loved method of travel for Americans, and some of its great roads are iconic, such as the famous Route 66.
Taxi service varies significantly from one city to another, and is often not available in country areas at all. In big cities, taxis are readily identifiable and can be found effortlessly. There are copious underground train systems in operation in main cities including New York (subway), Washington, DC (metro), Boston ('T'), Chicago (train) and San Francisco (BART - Bay Area Rapid Transit); others are being planned or built. There are also numerous tramway and trolleybus systems, counting the much-loved antique trams found in San Francisco, though in many cities a car will be needed to get around, due to lack of public transport.