Transportation in Mexico is very different from America. Cars are just as prevalent, surprisingly! According to our taxi driver, this is because about 30 years ago many major car manufacturers began offering very low down payments and very low monthly payments. So everyone here jumped on the car bandwagon. I'm very glad to not be driving here, however. Cars supposedly drive on the right, like in America; however it's more of a guideline really. People swerve around each other all the time, and there aren't actually any lines painted on the streets. Oaxaca itself is a morass of tiny one-way streets and only occasionally-working stoplights. On the highways, there are no speed limits. Instead, there are speed bumps every mile or so.
Probably the most prevalent car brand in Oaxaca is Nissan. All of the taxis are Nissans, and many personal cars as well. After that is Ford and Chevy (and a bunch of VW Beetles for no good reason because VW has a factory in Puebla). Those four account for perhaps 80% of the cars I've seen so far. The rest is a smattering of Seat, Peugeot, and Renault. I've seen very few other Japanese cars here -- maybe one or two each of Toyota, Honda, Suzuki, and Mazda.
Besides walking, the other major way to get around in Mexico are the buses. The way buses seem to work is a man wakes up one day, buys a bus, decorates the holy heck out of it, and makes up a route. Then he drives that route whenever he feels like it, stopping at unmarked and seemingly random points along the way to pick up and drop off passengers.
It's kind of a neat way to do things, when you think about it. Routes are completely determined by supply and demand. If there are lots of people who need to get from one village to another then many buses may drive that route. If there are only a few, then a bus driver may only drive by that way once or twice a day. They are completely independently owned and operated (as far as I can tell), so the government doesn't have to pay for them and the incentive for the drivers to do a good job and have useful stops and hours is making their living! When my parents and I went to Zaachila (and a few points in between there and Oaxaca) we took several buses, and they were always clean, rarely overcrowded, and almost always stopped exactly where we wanted to go.
Of course I know that transportation is different in different countries, but I never would have thought that the very basis of the bus network would be interpreted in this fashion! What a fun way to mix it up!