Taxis in Mexico City: when possible, avoid the street taxis (the green ones are called "ecológicos"). Preferably, call for a taxi stand ("taxi de sitio") or radio taxi ("radio taxi"), even though the rate is somewhat higher. As an additional precaution, write down the license plates of the taxi. Airport taxis are yellow in color and have the airport symbol (the outline of a plane) on the doors. Airport taxi fares are paid in advance at the airport the special ticket windows.