This article illustrates the problem of urban transport. To that end it takes the city of Santiago (Chile) as subject of analysis. First, the paper introduces the concept of transport system and explains its dynamics due to the impacts on the urban environment. Next, some characteristics of Santiago’s transport system and, for comparison, some of the urban transport in London, are presented. Certain non-intuitive facts are then concluded from these data. Finally, some consequences for urban transport policy are derived.