Three major dimensions are of concern to depict the concept of modal competition:
- Modal choice competition is the most basic consideration concerning modal competition. On the above example, three modal choice scenarios are considered for two modes. The first two cases (1 and 2) are instances where only one mode is used since it represents the most efficient (or the only available) solution. This solution is derived by comparing the two available modes and choosing the one that answers the best mobility requirements between locations A and B. Case three represents another possible solution where the two modes are used in a combination of two segments with a point of transfer. This alternative is a multimodal transport solution which is increasingly been applied over transport systems. It enables to use modes over the segments they are comparatively the most efficient.
- Infrastructure or route competition represents another dimension where modal competition occurs over the usage of a specific infrastructure or route. Three scenarios are generally possible. In the first case (4), there is simply no competition as one mode has a monopoly over a route, either because of technical (a subway line for instance) or regulatory (car-only expressways) reasons. The second case (5) represents an exclusive sharing arrangement where two modes are using the same infrastructure, but at different moments. Infrastructure use by rail passenger and freight is a relevant example, as both may be using the same infrastructure but not at the same time. A decision has thus to be made about which mode gets priority in terms of available capacity. In North America, priority is given to freight while in Europe priority is given to passengers. The third case (6) illustrates a situation where two modes have a mutual sharing arrangement. Access to infrastructure is generally unconstrained but the total capacity is obviously the result of respective levels of usage. Cars and trucks are commonly sharing the same road infrastructure.
- Market area competition is the third dimension of modal competition, which is tied to geographical considerations. It mainly concerns transport terminals that are drawing users and their associated flows from their surroundings. In the above example, locations A and B have their own exclusive market areas over which that have a clear advantage. Competition occurs over a portion of the territory where the respective advantages of locations A and B are not clear; the competition margin. Technical improvements have increased competition margins as terminals such as ports are competing over overlapping market areas that may span whole regions.