One of the fundamental activities in transportation planning is forecasting. The present thesis has aimed to develop and test advanced methodologies in the areas of (i) scenario building and (ii) freight transport demand modelling. Scenario building plays a key role in forecasting. In real world, numerous factors have an influence on the transport system. Factors fall into different domains, among the others demographics, economy, and energy. Factors can be characterised according to trend and impact on the transport system. The construction of scenarios is based on these factors. The selection of scenario variables from these factors has been the first aim of the research presented here. We have collected experts’ judgements on the importance and trend uncertainty of factors by an online survey performed within the activities of the European project OPTIMISM of the Seventh Framework Programme. Then, the Multiple Criteria Decision Analysis (MCDA) methods ELECTRE I and II have been applied with the aim of selecting the most important and trenduncertain factors. The combination of the expert-based online survey and the MCDA has allowed to identify the factors that can be selected as scenario variables. The product of this part of the research is relevant to planning studies, in particular those that are carried out at national and regional levels. As to freight transport demand modelling, we have carried out, for a real case, a structured analysis of the production and consumption components of the economy of a region. The economy is of interest for the transport planner as it is the key determinant of freight transport demand. Due to the complexity of data and their linkages, as well as the difficulties of data gathering, methods of “non-survey” type are frequently used, thanks to their moderate requirement of data resources and “standardized” analysis process. We have applied Input-Output modelling, Location Quotients methods and a Bi-Proportional model to the case of the Lazio region. The activities have been performed within the PRMTL project (Piano Regionale Mobilità, Trasporti e Logistica della regione Lazio). Based on data provided by ISTAT, we have succeeded to draw a picture of the production and consumption levels of all the municipalities in the Lazio region, and of the trade flows of products among the twenty Italian regions. The analysis that has been performed provides the basis for the estimation of the impacts on freight traffic flows of changes in the economy, once the coupling of the data and modelling system developed with traffic data is accomplished (traffic data are available from the European project ETISplus - European Transport policy Information System).