Americans don't seem to use buses much, but buses are economical and possibly more efficient than driving and trying to locate unfamiliar streets and neighborhoods while driving a car. If you use buses, you should learn as much as possible about schedules and destinations which are numerous but not confusing. Buses are safe. We rode them for two years constantly in Latin America without a problem. You can hail one en route, showing the number of fingers to indicate size of your party.
Some taxi drivers speak English and provide valuable information.
Most don't speak it, but will understand a little and estimate a price. Sometimes they have trouble finding the address, but if they do, they still stick by the quoted price. Drivers don't expect tips for the ride, but if they handle baggage, a tip may be earned. If you decide to live in Mexico, you will want to get well acquainted with taxi service. You'll use it often.