The transport infrastructures are the whole of the fixed Installation S which it is necessary to arrange to allow the Circulation Véhicule S and more generally the operation of the Système S of Transport.

The infrastructures are generally specific of a Means of transport, and are conceived to allow the circulation of certain types of vehicles, more or less diversified. According to the means of transport, the connection between vehicles and infrastructure is more or less close, the extremes being the vehicle Tout-terrain, almost completely independent, on a side, and the Cabine of Téléphérique, completely related to its infrastructure (carrying cable and tractor cable), other. In extreme cases, the infrastructure constitutes the totality of the transport system; it is the case for example Canalisation S intended for the transport of Liquide S of Gaz or products in powder form, such as the Aqueduc S and Oléoduc S.

The infrastructures are generally organized in networks comprising nodes and bonds. Thus the Railway network consists of Gare S connected between them by lines. The important nodes, like the stations, the ports and Aéroport S are also the contact point and of exchange between two or several modes of tranport.

The transport infrastructures are a paramount element to guarantee the freedom of displacement of the people and goods, and to ensure the operation and the development of the economy. Their creation, which is an important part of the Town and country planning, generally requires heavy Investissement S. that explains why they are generally taken of load by the public power. However, this one delegates some sometimes, for reasons of Financement or know-how, construction and the exploitation with Entreprise S private n the other hand of the perception of a Péage (it is the case for example Channel tunnel and, more recently, of the Viaduc of Millau).

The Voirie, which includes/understands the whole of the road ways, has the effect of being in all the countries a public space, opened with all free (except obviously the private or conceded ways). It is not the case of the other transport infrastructures (as the railway network) which constitute the private spaces reserved for the exclusive use of the competent owners).

The infrastructure designates in a strict sense the lower part, the base of a way. The term is opposed to superstructure. One can, in certain cases, to distinguish both: thus in a line of Railroad, the infrastructure, strictly speaking, is the platform of the way, on which one could as well establish a road way, while the superstructure is consisted the Railway itself (rails and cross-pieces). In the broad sense, the transport infrastructure indicates the unit and includes all the elements necessary to the normal exploitation: Catenary S, Indication, signal boxes, control tower in the airports, etc, like all the buildings related to the use of the aforesaid the infrastructure.

Principal transport infrastructures

• Highway network
• Railway network