24: Insights on Freight and Commercial Vehicle Data Needs

Most of the analysis and evaluation of transport projects involves the determination of some kind of quantitative data that cannot be directly measured “in the field” but needs to be estimated with the aid of mathematical models. Such is the case of the estimation of equilibrium flows; where “equilibrium” is understood to mean a system's state in which the vehicle flows are such that enable compatibility of the level of service perceived by the transport users at all stages in the modelling process. To compute equilibrium flows, demand and supply (network) models are needed for all the modes and commodities participating in a given transport system. Both types of models are generally intensive in data use, though requiring different types (and quantity) of data and data processing methods. Demand models usually require a wider variety of data than their supply counterpart, mostly because they are essentially based on econometric techniques. For these reasons, the aim of this chapter is to review several aspects of transport data from the freight demand models (FDM) perspective.