11: Design and Implementation of PECAS: A Generalised System for Allocating Economic Production, Exchange and Consumption Quantities

PECAS is a recently-developed, generalised approach for simulating spatial economic systems. It is designed to provide a simulation of the land use component of land use transport interactive modelling systems.

PECAS stands for Production, Exchange and Consumption Allocation System. It uses an aggregate, quasi-dynamic equilibrium structure with separate flows of exchanges (including goods, services, labour and space) going from production to consumption based on variable technical coefficients and market clearing with exchange prices. Flows of exchanges from production to exchange zones and from exchange zones to consumption are allocated using nested logit models according to exchange prices and transport (dis)utilities. These flows are converted to transport demands that are loaded to networks in order to determine congested travel disutilities. Exchange prices determined for space inform the calculation of changes in space thereby simulating developer actions. The system is run for each year being simulated, with the travel disutilities and changes in space for one year influencing the flows of exchanges in the next year.