5: Estimation of an Origin-Destination Matrix for Urban Freight Transport. Application to the City of Seville

This work presents the process followed to estimate an origin-destination matrix for freight transport in the city of Seville. The focus lies specially on the data acquisition process, which is normally one of the main obstacles to be faced by this type of analysis. The model used, based on entropy maximisation, and the solution algorithm, including Frank-Wolfe's linear approximations, are equally described. Results are presented graphically and then compared with vehicle flows observed from reality, allowing to extract conclusions for the validation of the model.

This paper describes work that is part of a project aimed at obtaining a description of freight movements in the city of Seville. The main tool for carrying out the analysis is the commercial package EMME/2, which performs equilibrium assignments (traffic flow calculations) using an urban network divided into zones and an origin-destination (O-D) matrix, which reflects how many vehicles travel between every pair of zones. An O-D matrix for passenger automobile traffic was already available for the city, and so passenger traffic assignments were already performed. This paper will show the process followed for estimating O-D matrices for freight transport vehicles, as well as carrying out a passenger automobile traffic, freight traffic conjoint assignment. A comparison between estimated and actual freight flows will then be made, identifying the weaknesses of the model and the need for further information.