Institute for Transport Studies (ITS)

Mode and shipment size choice models on data for individual shipments

Supervisor: Prof. Gerard de Jong

Mode choice in freight transport is usually studied in isolation. However, mode and shipment size are closely linked decisions. Large shipment sizes usually coincide with higher market shares for non-road transport, whereas there is a high correlation between road transport and small shipment sizes. Decisions on shipment size (or delivery frequency) need to be studied taking a logistics approach (e.g. reducing inventories by more frequent, just-in-time deliveries) that encompasses the more limited transport costs approach.

The Swedish 2004-2005 Commodity Flow Survey (CFS) is a unique data source in Europe. It details about more than 2.5 million individual shipments to or from a company in Sweden, with information on origin, destination, modes used, weight and value of the shipment, sector of the sending firm, commodity type, access to rail tracks and quays, etc.. Whilst the US Commodity Flow Survey has been analysed several times, its Swedish counterpart has barely been used for model estimation so far. Using this Swedish CFS, mode and shipment size choice at the individual shipment level can be explained from characteristics of the shipper, the shipment and transport time and cost on the networks.

Earlier work at ITS Leeds used the CFS 2001 to estimate mode and shipment size models. Multinomial land nested logit models were estimated on the CFS 2004-2005 in a Master Thesis project at Delft University of Technology in The Netherlands.

This PhD project will extend the models estimated so far on the CFS 2004-2005 in many ways:

  • estimation of different models for different commodity classes (observed heterogeneity)
  • estimation of models with different transport and logistics costs functions
  • estimation of mixed logit models following the random coefficients specification to account for unobserved heterogeneity
  • estimation of models where shipment size is treated as a continuous variable instead of discrete size classes, simultaneously with (discrete) mode choice.

Furthermore the project will look into the implications of these modelling options for the value of time and freight demand elasticities - the model outputs that are typically used to evaluate transport policies.

Suggested reading:

Jong, G.C. de and M.E. Ben-Akiva (2007) “A micro-simulation model of shipment size and transport chain choice”, Special issue on freight transport of Transportation Research B, 41, pp. 950-965, 2007.

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