A Sim's route was defined as a path from point A to point B, and a maximum time. If the maximum time was reached, the route was a failure and would reflect as increased congestion. If a Sim encountered mass transit along its route, it would attempt to take it using the same pathing algorithm as car travel. However, if the route failed while using mass transit, it would never try it again, even as mass transit service expanded and new bus and subway lines/stations were added.

The most recent SimCity was supposed to be more realistic in its route planning and simulation by giving each Sim a home, a workplace, etc., and repeating routes on a daily basis instead of a random sampling of routes, but this didn't make it into the final game.