Intermodal transportation can be used under specific conditions. At start, the load unit must be suitable for intermodalism, which implies that the maximum weight of the load unit should be under 25 tons (regulatory limit to the weight of standard and domestic containers). Intermediate (parts) and finished goods are particularly suitable for intermodal transport because they can be assembled in such load units. There must be a modal continuity where load units are able to switch from one mode to the other. The intermodal terminal is the core component of this continuity, which can also be improved with a suitable regulatory framework, particularly if borders are crossed. Although the threshold is not absolute, distances above 500 km as usually required for intermodal transportation to be effectively used. A shorter distance can be serviced by trucks in a more competitive fashion.
The cargo value is also a factor with intermediate value cargo the most suitable to be carried by intermodal transport. Low-value cargo is usually carried in bulk while high-value cargo tends to be carried by air transport because transport time is more important than transport cost (high value to weight ratio). Intermodal transport is more suitable when the frequency of shipments is continuous and stable. Under such circumstances, transport assets can be allocated as continuous services over stable routes.
When the above conditions are satisfied, the application of intermodal transport can lead to a set of outcomes. Intermodal transport is expected to reduce total transportation costs, mostly because of the benefits of economies of scale over transport markets that were previously less prone to their application. A modal shift is also expected, particularly towards modes having a higher capacity and efficiency, such as rail or barges. Each mode tends to be used for the conditions for which it is the most suitable, with distance being a key factor.
Intermodalism requires the consolidation and deconsolidation of load units into large batches (also called composition and decomposition), such as intermodal trains. This takes place at intermodal terminals, which become the points of convergence and divergence of freight flows. It also possible to have a higher load factor, with more full truckload transport as well as a higher level of asset utilization. Changing the network structure of freight transportation with intermodalism usually results in less empty backhauls for vehicles.