1. Gravel or Dirt
If you are on this, you should have started here. If not, you made a bad choice. Stay on the pavement.
2. Paved, No Lines
Usually residential, sometimes an alleyway. Rarely goes anywhere. Never has anything more complicated than a STOP sign. Do not turn onto this road from another road, and generally try to avoid getting on too many of them on a row.
3. Two Lane Road
The classic, with a painted center line and usually some edge lines. These can go for quite a ways, which may or may not be useful, but they also every often come with traffic lights and signs. Signs state useful information; use them.
4. Multi-Lane Road
These have shoulders, a median, multiple lanes in each direction, and are almost always going somewhere. There are usually signs to indicate where they are going. If a multi-lane road develops fewer lanes, and you do not know where you are going, consider turning around. If you do know where you are going, if not specifically where you are at the time, it is okay to keep following.
5. Divided Highway
Often useful for going between towns or points of interest, they can be difficult to turn around on, but are great for going fast. These usually have numbers of some description.
6. Controlled Access Highway
A step up from a divided highway, controlled access roads are the ones with exit ramps and bridges. Not all of them are toll roads, but some are. These nearly always have numbers of some description, but all of them should have very useful signs and destinations.