Choix de variantes d'infrastructures routières : méthodes multicritères

This study provides a tool by means of which a road planner, usually a civil engineer, can achieve a durable infrastructure of high quality, acceptable to all parties concerned. The various elements which facilitate the work of planning are united into a modernized methodology for the elaboration of road projects, called a methodology of concert. After analysing the sort of problems encountered in the planning of road infrastructure (Chapter 1), the author classifies the main causes of these into a hierarchy. This brings to light many factors which may stem from the structure of the project, the environment or from the various participants. The modernization of the working methods of road planners is a highly practical idea based on case studies (Chapter 2). The particular study on which this work is based is the "Comparaison de variantes 1999", made on the A 144 road between the cities of Villeneuve and Le Bouveret. From an initial group of four variants, which were a source of much contention between the interested parties, an optimal and consensual solution, called "Solution COPIL", was evolved in seven months, by means of this study. The choice of this solution was based on a method of multicriteria decision analysis of a completely aggregational form. This used the weightings defined by all the political partners in the study. The present author was allowed to sit in on about fifteen working sessions of the Technical Group and of the Guiding Committee, which consists of the political partners. The examination of this particular case provided him with much valuable information about the process of elaboration of a road plan. The requirements and aims of road infrastructure are analysed (Chapter 3). Here, the focus is on the definition of individual and collective needs and the evolution of social expectation of the general public. The implementation of public policy is then examined. Particular emphasis is laid on the principal public policies whose spatial incidence affects the road plan : land distribution, transport and environment. Some attention is paid to the consideration of mobility, its value, characteristics and future developments. The difference between the standard and the norm of road infrastructure is described explicitly. The various stages of the process of elaboration of a road plan are analysed in depth. (Chapter 4) Particular attention is paid to the initial stages of impulsion for the elaboration of the project and of the identification of needs, since these influence strongly the quality and the acceptability of the project. The author then proposes that the various stages of road infrastructure be presented in the form of a life cycle of which the present study only concerns some aspects. Various special procedures are then analysed critically in order to extract propositions to be integrated into the methodology of concert. The type of partners in the road project and the characteristics of the relationships between th