Through a study with experienced driver-navigators, we have deduced some principles as to how route descriptions are constructed and expressed by humans. Some of these principles are implementable, and a rough outline of a program is presented. Given a plan of how to go from A to B in a city, the program produces a non-linguistic object that represents all the route information needed to present the route to a specific driver. A verbal description of that object is then producedl. The goal is to incorporate verbal descriptions in route guidance systems, primarily aimed at driver navigators with some knowledge of the city. Furthermore, we speculate into what kind of cognitive processes are involved when humans choose and describe routes.