This degree project was carried out at the transport design office Setec International, in Paris, from August 3rd to December 18th, 2020. I was part of the team in charge of the post-evaluation of the A150 highway.Permanent observatories are organizations that bring together public and private actors in order to collect early and systematically data to analyze the effects of a transport infrastructure. They have been set up since the 1980s, mainly on French highways. In particular, they contribute to the production of a posteriori assessments known as "LOTI". The objective of this project is to qualitatively evaluate the contribution of these observatories to socio-economic evaluations, both for "classic" and "wider economic" effects. The methods used are the "practical" experience of carrying out the LOTI assessment of the A150, the study of reports describing the results of the A39 and A71 observatories, and the analysis of reports from the State services on the quality of LOTI assessments.The permanent observatories limit some of the pitfalls of ex-post assessments linked to the measurement of classic effects, especially traffic and journey times. They also highlight the effects of a construction site and the strategies of the economic actors. However, they retain certain limitations of ex-post assessments such as the spatial and temporal scale, or the concessionaire's willingness not to disclose certain data. Thanks to early and regular data collection, permanent observatories seem to contribute significantly to the analysis of classic and wider economic effects, they limit the risk of poor quality analyses. Nevertheless, they do not seem indispensable for the production of studies of satisfactory quality.The rare data available on the cost of the observatories suggest that it is very low compared to the amounts invested in construction. Thus, in comparison with these costs, this end-of-study project gives a positive qualitative assessment of the contribution of permanent highway observatories to socio-economic studies. However, this study is limited by the amount of data available due to the non-mandatory nature of setting up permanent observatories.

La promotion du transport ferroviaire de marchandises permet d’améliorer l’impact environnemental du transport de marchandises, à travers la réduction de la part modale de la route, qui est responsable d’environ un quart des émissions européennes de CO2. L’objet de cette thèse est d’analyser les flux de marchandises afin de proposer des solutions opérationnelles qui permettraient d’augmenter la part de marché du transport de fret ferroviaire, notamment grâce à une meilleure utilisation des terminaux intermodaux. La première partie de la thèse fournit une synthèse des principales modèles théoriques concernant l’analyse de la demande et de l’offre de transport de marchandises, afin d’analyser le lien entre activité économique et transport de marchandises. Une analyse détaillée des sources statistiques disponibles au niveau européen, national et régional, est aussi fournie. Dans la deuxième partie, une application au cas des chantiers de transbordement rail-route en France est présentée, et une comparaison avec d’autres pays européens est réalisée. L’objectif de cette analyse est d’estimer la demande potentielle de transport combiné, d’évaluer la productivité des terminaux intermodaux et d’étudier l’impact socio-économique et financier des investissements dans les terminaux intermodaux, en évaluant également la possibilité des nouveaux montages financiers (PPP). Les résultats de l’analyse montrent un large potentiel pour le transport combiné, en particulier en lien avec l’activité des ports maritimes, et une productivité faible dans les terminaux existants. En conséquence, cette analyse suggèrerait de concentrer les investissements sur un nombre limité de sites à haut potentiel, afin d’attirer des investissements privés et optimiser l’utilisation des fonds publics. Les implications politiques de cette analyse sont multiples : elles concernent d’abord le gestionnaire d’infrastructure et les opérateurs ferroviaires, qui doivent mieux planifier les investissements en fonction de la demande commerciale. Elles concernent aussi l’Etat et les collectivités locales, qui doivent optimiser l’utilisation des fonds publics en favorisant les localisations à haut potentiel. / The promotion of railway modal share has large benefits on the environment by reducing the modal share of road transport, which is responsible for about one-fourth of European CO2 emissions. The aim of this dissertation is to analyse freight transport flows in order to provide operational solutions to increase the modal share of railways transport through a better use of intermodal terminals. In the first part of the dissertation a theoretical survey of freight transport models is provided, in order to show the linkage between freight transport and economic activities. A comprehensive analysis of data sources at European, national and regional levels is also provided. In the second part of the dissertation an application to the case of railway intermodal terminals in France is provided, with some comparisons to other European countries. The scope of the analysis is to estimate the potential demand of combined transport, to assess the productivity of intermodal terminals and to evaluate the socio-economic and financial impact of new investments in terminals, also through new project financing schemes (PPPs). The results show a large potential for railway intermodal transport, especially in connection with maritime ports, and low productivity in existing terminals. As a consequence it’s fundamental to concentrate new investments in a few high potential locations, in order to attract private investments and to provide a better use of public funds. The policy implications of this analysis are multiple: it concerns first the railway companies and the infrastructure managers, which should better plan their investments according to commercial needs. It concerns also governments and regional authorities which should better concentrate public funds on optimal terminal locations.