Development of a Statewide Commodity Flow Distribution Model Using Composite Friction Factors

In a traditional four-step urban transportation demand forecasting modeling, passenger trips in a zone generated in the trip generation step are distributed to other zones using various algorithms, such as a gravity model. However, this method does not apply well to commodity flow distribution because commodities are transported by various types of trucks depending on types of commodities, which eventually affect the number of trips generated. A new concept for distributing commodity flows to zones using an enhanced gravity model with composite friction factors was developed and the concept was applied to commodity flow distribution in the state of Utah.