Multimodal transport is considered as an important solution to tackle the sustainability concerns of the freight transport system. Multimodal transport is the movement of goods by at least two different modes of transport. Governments have set goals and taken actions to promote and stimulate multimodal transport. Despite the awareness and actions, the modal split has remained constant throughout the last decade in Belgium and Europe. A large body of research that demonstrates the economic and sustainability benefits of multimodal transport exists; it either compares the transport modes directly or focuses on multimodal transport of containerized goods. However, other cargo types are used in the supply chain as well, and they are, to the best of our knowledge, not considered in the research on multimodal transport and transport modelling. The incorporation of different commonly used cargo types in a framework that assesses the economic and sustainability potential of a modal shift of freight is new and needed to address the sustainability challenges which the freight transport sector is facing. This incorporation gave rise to the research of this thesis, which aims to answer the following question: What is the potential for multimodal transport taking into account different cargo types in transport modelling?
The cargo type is the classification, based on its appearance, of a load of goods that is transported or is intended to be transported. The cargo type can consist of either liquid or solid bulk without packaging, standardized units (such as pallets or containers), or unstandardized units (such as parcels). The first section of this thesis focuses on the importance of the cargo type in multimodal transport. In practice, the transport operations and decisions in the supply chain are influenced by the cargo type. The costs related to transshipment, inventory and transport are highly affected by it. Therefore, the different cargo types should be considered in the modal choice analyses (chapter 2).
The second section examines the potential for a modal shift of different cargo types. Special focus is given to the sustainability of the transport system in Belgium. First, an initial feasibility analysis was performed for a modal shift of palletized freight towards the inland waterways. The Location Analysis Model for Barge Transport of Pallets (LAMBTOP) was developed within this PhD research to do so. The model identifies the optimal transshipment locations, as well as the palletized transport flows that can be cost-efficiently shifted towards inland waterway transport. First, the model is applied to the flows of palletized building materials within Belgium (chapter 3). In a second stage, LAMBTOP was extended by considering the total logistics costs to include the reliability of the transport mode and the depreciation, shelf-life and value of the goods. In addition, the methodology was enlarged to the European scale (chapter 4). Cost-efficient transport flows were found, thus showing the potential of this market.
A second model was developed, called the TRansport Agent-BAsed Model (TRABAM), to consider different commonly used cargo types. The model incorporates the cargo type into the decision process with regards to the vehicle and mode choice. A differentiation is made between five cargo types (liquid bulk, solid bulk, containers, pallets and mobile units), as they all either positively or negatively influence the feasibility of a modal shift. TRABAM contributes to the MATSim freight extension by adding the multimodal transport and the cargo type used to it. By modelling the transport flows according to the commodity type and cargo type used between 4.934 zones subdividing the Belgian territory, TRABAM is more disaggregated than the existing freight models for Belgium (chapter 5). The shipments are generated via regression techniques based on aggregated data and economic and demographic data (chapter 6). The mode choice decisions are taken by the agents in the model, which are the Belgian carriers. TRABAM considers real-world Belgian logistic service providers, including their existing vehicle fleet and depot locations. In addition, passenger car flows are imbedded in the model as a base layer and for peak-hours. Import, export and transit flows are assigned to the agents representing foreign logistic service providers. Each domestic shipment is assigned to an agent that optimizes its routing, stop sequence, vehicle and mode choice and its departure time via an iteration process (chapter 7). The output consists of information on the movements of individual freight vehicles throughout time and space on a one-day basis. The multimodal potential for different cargo types is calculated accordingly (chapter 8). Containers, solid bulk and liquid bulk show the highest shares for rail and inland waterway transport (29,6%, 35,8% and 48,9% of the volume, respectively). The pallets on the inland waterways have a potential of 4,3%. When the variable costs for road transport would increase by 10%, it leads to a limited increase of 0,8% of the rail and inland waterway transport share. Pallets (+2,4%), solid bulk (+3,9%) and liquid bulk (+5,9%) are more sensitive to road transport cost increases. The output is also linked to vehicle-, traffic condition-, environment-, loading rate- and infrastructure-dependent emission factors. Two applications, i.e., air pollution in the Brussels Metropolitan Region (chapter 9) and off-hour deliveries to Walloon supermarkets (chapter 10) – are presented. TRABAM is capable of answering pertinent freight transport research challenges.