A very large number of development issues would need to be covered in a comprehensive text. Here a selection is limited to three: transportation, housing, and community and economic development. These represent three of the most important and difficult of today’s development issues. Transportation is the essential ‘connector’ of activities. Upon its adequacy depends the efficiency and convenience of settlements. The importance of transportation in the urbanization process was discussed in Chapter 2. In Chapter 12, the focus is on its centrality in modern society, the problems to which it gives rise, the need to link transportation to land use, and the huge and expensive measures needed to deal with these problems. There is also a caution: our understanding of the complexities of metropolitan areas (within which four-fifths of the population live) is limited: in the current state of knowledge, we are unable to plan transportation systems with confidence about their adequacy or even their effects.