Planning is an extremely complex discipline, arguably the most difficult of all those relating to transportation. It addresses sustainability of the transport plan through integrated policies. Like geometric design, it has shifted from a focus on moving traffic to being a multidisciplinary activity. In this chapter, the focus is, however, on the mechanisms of technical analysis of transportation planning rather than on its broader philosophies. This is to ensure that the geometric designer will, at least, have some understanding of the outputs of the transportation planning process and how they impact on project design.