Planning Transport Systems
Planning of transport systems can generally be classified under two categories regarding the time scale—short-term or short-range and long-term or long-range. The transport planning process generally includes five steps: inventories of current systems and collection of relevant data; model development to be applied to forecasting demand and supply; generation of alternate plans; selection of the preferred plan; and implementation of the preferred plan. Specifically, planning transport demand and supply in the planning context is based on their modelling. In general, it consists of four steps: generation and attraction of traffic/transport demand flows; distribution of traffic/transport demand flows; modal choice and modal split; and assignment of traffic/transport demand on the links and routes of given network(s). Specifically, for planning the urban and sub-urban road (and rail) networks, two types of traffic assignment models are commonly used—the user equilibrium and the system optimization assignment model.