Avoid flagging a regular taxi—taxi assaults are a plague peculiar to Mexico City, and tourists, often toting cameras and recent purchases, are especially vulnerable. Sitios, or radio cabs, offer a convenient, reasonably-priced and safe way to get around town.

Maroon or orange colored, or white with orange stripes, radio cabs usually add a surcharge to the amount registered on the taximeter. The estimated price of your trip can be quoted to you over the phone. Only take radio cabs that have been specifically summoned; do not hail a sitio on the street. Hotels and restaurants are accustomed to calling radio cabs for their guests and clients.

Two of the best-known and most reliable companies are Servitaxis (5516-6020) and Taxi Radio (5566-0077).

Regular cabs come in two colors, yellow or green, but mostly one shape: the Volkswagen "beetle." A cab displays the word "Libre" ("Free") in the front windshield if it's available. Ensure the taximeter is working before getting in. If it's not, wait for another cab—such an irregularity could be a sign of a rogue taxi. After 10 p.m., a 20 percent surcharge is added to the fare.

Upon arrival in Mexico City, take only taxis belonging to the special airport concession. Prices are fixed according to destination and tickets can be purchased at clearly marked booths found both in the baggage claim area and next to major airport exits. Beware of hustlers offering transportation in unauthorized vehicles; they charge more and may be unreliable.