Intermodalism involves the organization of a sequence of modes between an origin and destination, including the transfer between the modes. Its main goal is to connect transportation systems that could not be connected otherwise because they are not servicing the same market areas due to their technical characteristics. However, each segment is subject to a separate ticket (for passengers) or a contract (for freight) that must be negotiated. Mutimodalism is simply an extension of intermodalism where all the transport and terminal sequences are subject to a single ticket or contract (bill of lading) that can be assumed by a single integrated carrier.
The differences between intermodalism and multimodalism appear to be subtle, but they are fundamental. Although multimodalism may look more efficient at first glance since less transactional costs are involved for the user, it is not necessary the most efficient and sustainable. A multimodal transport service provider will be inclined to use its routes and facilities during the transport process, which are not always the most convenient. The main purpose of a 3PL is to maximize the use of its assets, which could be at odds with the benefits of its users.
Transmodalism involves connecting different segments of the same mode between an origin and a destination. It tries to reconcile different modal services on the same network. There is no specific term if transmodalism takes place as a single or separate ticket or contract. Transmodalism is common for air transportation since passengers can easily book a ticket between two locations, even if it involves transiting through an intermediary airport and using separate carriers. The strategies of air carriers particularly relied on transmodalism with the setting of major hubs that maximize the number of city-pairs serviced. For freight transportation, transmodalism is more challenging since it was conventionally complex to switch load units within the same mode because of the large amount of handling required. Paradoxically, it is the development of intermodalism that has favored the setting of transmodalism since it incited the development of long-distance transportation services and an increase of container volumes to be handled across the same mode.
For maritime shipping, transmodalism took shape in the setting of intermediate hubs such as Singapore, Dubai, and Panama, connecting deepsea and feeder services. For rail, the North American rail system and its landbridge are interconnected at major transmodal hubs such as Chicago. The Eurasian landbridge is emerging on transmodalism as well.