Integrated urban transportation and land use modeling by application of system dynamics

The spatial allocation of land uses and vehicle route selection within an urban network are both dependent upon travel times between zones in an urban region. These location and accessibility components form the basis of a time dependent feedback structure linking land use and transportation planning. Integrating algorithms for land use allocation, mode choice, and route selection is the next step required for comprehensive urban planning. However, any integration of existing models still requires exogenous estimates of future population and employment.

Predictions of the distribution of land uses, travel mode, and route selection are all based upon modeling choice behaviors. Similarly, choice behavior modeling can be extended to virtually all elements of the urban structure. Drawing upon System Dynamics, and utilizing Forrester's concepts of urban modeling, a truly integrated model can be developed free of outside input for future population and employment levels.

The feasibility and utility of the Dynamic Urban Land Use - Transportation Model are demonstrated through the use of a hypothetical urban region. Given a set of initial conditions, the model simulates the choice behaviors that determine future population movement, employment opportunities, and housing availability, and allocates these elements to zones. Mode and route selection for the home-to-work journey are then simulated and become inputs for future spatial allocation. Analysis of the effects on the urban system as a result of a variety of transportation and land use policies is included to demonstrate the usefulness of the methodology as a decision making tool.