The city center is approximately 45 minutes from the airport, and you can reserve a taxi or private vehicle after exiting baggage claim. The metro—which offers air conditioning and female-only compartments—is an affordable, reliable, and environmentally friendly option, but is also congested with heavy crowds. Taxis are required by law to register as commercial vehicles, and they do have meters, although many drivers prefer to set a pre-paid flat rate. Surcharges will be applied for extra baggage, night rides, and tolls. Buses, usually run by the government, provide a cheap and convenient mode of public transportation. New features like air conditioning and low-floor lifts are being installed on city buses to improve the system and to draw private car owners away from busy roads. An auto-rickshaw, or tuk-tuk, is a three-wheeled motor vehicle for hire. Generally green, yellow, or black in color, auto-rickshaws have regulated, metered fares, and are common throughout the city. Private vehicles also povide a cheap, flexible, and comfortable option, but be sure to check that the car is licensed for tourists.