In Santo Domingo we have 2 kinds of buses:
OMSA buses: the government buses with scheduled stops, they come in 3 kinds: the ones without air conditioning and the cheapest ones, the ones with air conditioning and the express ones that make less stops. If you want to get off you simply pull the cord.
Union buses: property of the various transport unions, the route they drive is usually indicated by a piece of cardboard with the number of the route on the main windshield, visible so that we can stop the bus by stretching and arm and moving the index finger up and down (weird I know). On these buses there's a man hanging on the door called "cobrador" who will collect the fare and shout the route while on the road. Those buses are usually called "voladoras" because they drive like maniacs and at high speeds, and have no scheduled stops so if you want to get out you either shout "déjame" (let me off) or you tell the cobrador who then will signal the driver to stop by knocking on the carrocery of the bus.
There are two methods, that I know of, of getting around from place to place in Santo Domingo:
There are the Publicos, which are public cars, drivers will drive and honk constantly, when they are looking for passengers. . . until they get one. They are cheap and will usually get you where you wanted to go.
And the Guaguas (sounds like wawas).. which is the Caribbean spanish word for "Bus"... wherein another spanish-speaking countries, "camion" or "autobus" is more common.
You can find any of these anywhere you are and functioning well as long as there's gas in the country for transportation.