Well, I travel very....well....cheaply. I catch Conchos (the public cars) and Guaguas (the minivans) mostly. The Conchos have a letter sign on the outside doors (K, G, N, M, etc.) and on the inside of the window on the passenger side should be some sort of sign from the transportation people and they should also have an ID hanging from their mirror.
I catch Guaguas to visit folks in Sajoma and other campos such as Hatos de Yaque, I realy can't tell you how to distinguish if they are legit or not other than the fact that if there are no other people in them, do not get on.
Sorry I don't have more information. Ijust pretty much now know which cars to catch to where and the guaguas. Usually the Guaguas have a person that collects the money and this person is usually leaning out of the door yelling out the destination "La Mata! La Mata!" (for Sajoma) or "Licey! Licey!", "La Vega! La Vega!", etc.
I've caught the Onsa before, but only when with Dominicans.
I catch motoconchos only when it is really hot and I don't want to walk the 3 blocks from the Concho stop to my house.
I take only certified taxis at night, I used to take Conchos at night until my son's father found out and yelled at me so loud and so fast in Dominican Spanish that even though I only understood 25% of what he said, I knew that I was not to do it again. LOL
SHALENA