Source: adapted from A. Bertaud (2001) Metropolis: A Measure of the Spatial Organization of 7 Large Cities.
Cities can structurally be classified as polycentric (more common) or monocentric and major urban mobility flows as organized or disorganized (more common). Flows can be classified as primary, reflecting main road and transit corridors converging towards main employment and population areas, and as secondary, often linking sub-centers. Cities with a higher reliance on public transit tend to be monocentric with a higher level of organized flows, while cities depending more on the automobile tend to be polycentric with a more disorganized structure of flows.