Speedy course or scenic route? Interstate, state highway, or back road? And oh, those one-way streets! To plan your trip, you have to know both the road systems and type of travel you're looking for. The best way to do both is to consult the map's key (also called a legend). Usually located in a small box at one corner of the map, it typically contains the following important data:

• The map's scale--usually 1 inch (2.5 centimeters) equaling a certain number of miles or kilometers

• Classifications for local roads, state and federal highways, interstates, toll roads, and so on (these will also include highway markers--symbols for the different highway systems that also contain the highway's particular number)

• Population symbols that mark a town or city's size and its position on the map

• Symbols for man-made and natural landmarks