Trip distribution models are used to predict the spatial pattern of trips or other flows between origins and destinations. Models similar to those applied for trip distribution are often used to model commodity flows, retail trade, and store patronage.
TransCAD Transportation Planning Software provides numerous tools with which to perform trip distribution, including procedures to implement growth factor methods, apply gravity models, generate friction factors, and calibrate new model parameters.
TransCAD includes tri-proportional models which allow for another dimension of constraints. In tri-proportional models, groups of cells in the P-A flow matrix are required to sum to specified values. TransCAD allows the additional dimension to be applied for both growth factor and gravity models.
In addition to traditional trip distribution methods, TransCAD supports modern distribution techniques based on discrete choice frameworks to apply destination choice models at both aggregate and disaggregate levels. Destination choice models include shadow pricing options to ensure consistency between productions and attractions.