Transportation in CDMX
Mexico City:As one of the largest and most spread out metropolitan areas in the Northern Hemisphere Mexico City has many transportation options available. Of note the sprawling metropolis also has some of the worst traffic congestion in the world.
Thus a few tips:
Taxis: In general as advised by locals do not take a taxi. While most drivers are reputable there are of course some that are not. Experiences include purposely taking longer-routes or traffic to increase cost on the meter, being taken to an ATM to withdraw funds and so forth. Personally I feel for the drivers plight and know in New York income for taxi drivers has been decimated since ride-sharing came into the market. However from recent first-hand experience I took a taxi in Mexico City. Besides the taxi being uncomfortable and dirty, the driver purposely took routes to inflate what would have been a $5 USD fare via Uber into a $20 USD fare via the meter.
Uber: Your best option as flat fee regardless of traffic and usually more upscale and comfortable with real-time information and safety features associated with ride-sharing.
Busses: The Mexico City Bus System is extensive and in many parts of the metropolis the busses have dedicated barrier separated lanes, thus beating traffic. Of note many stops are in the middle of the road thus can be challenging to access via traffic, best practice, follow the locals.
Subway: A clean and modern system and cheap. However crowded. Thus be forewarned you will be jostled, pushed, crammed and so forth. Be aware of pick pockets, wear purses cross-body and so forth. Yet for time and efficiency cannot be beat.
For a primer concerning how to ride the busses and subway the following is excellent: Getting Around Mexico City: Guide to Public Transportation