Understanding a city’s spatial structure is essential to understanding its potential for different development objectives. According to renowned planning consultant Alain Bertaud, a long-time Principal Urban Planner for the World Bank, some urban shapes are just more compatible with environmental and social objectives. Some city layouts, for example, are unfavorable to the development of public transit; others not only increase public transit’s efficiency but also reduce residential floor consumption. Because urban spatial structures are highly resilient and evolve only very slowly, says Bertaud, a city’s spatial structure significantly reduces the range of available development options. In this report, the author explores the link between cities’ spatial structures and their performance in terms of transit use and motorization, air pollution, and poverty. Comparing monocentric with polycentric structures, he finds that the type of urban structure often defines the success or failure of policy objectives in these contexts.