Research on passenger transport covers all forms of public and private transport by air, land and water, both scheduled and unscheduled. It includes non-motorised and pedestrian transport. Passenger transport may be urban, rural, coastal, local, long-distance or cross-border, and involve one or more modes. Given the breadth of this theme, the research is primarily of relevance to planning, organisation and operation of passenger transport modes to the exclusion of freight.
Freight transport research deals with the movement of raw materials, semi-processed products, and finished products from supplier to consumer, and new and used consumer products back to supplier. It also concerns the movement of agricultural products and livestock. Freight movement is becoming increasingly intermodal and multimodal using local, regional, national and international systems. Indirectly, freight transport concerns the organisation and management of the supply chain and logistic services that determine the quantity and quality of freight transport, and commercial relationships between shippers and transport service providers.