The paper presents a survey conducted on the environmental impact assessments and the feasibility
studies for fifteen selected infrastructural transport projects all over the Italian territory and approved
under the so called “Objective Law”. The survey collects data concerning the demand forecasts, the
definition of alternatives and the cost benefit analysis, with their level of detail.
The aim of such work is to derive some general considerations about the quality, the transparency and
the contents of the assessment, in the context of the Italian normative framework.
For the analysed projects, it is possible to recognise a lack of contemplation to the definition and in the
construction of the demand forecast model, the use of extremely standardised schemes of comparison, the
presence of double counting and some theoretical errors concerning costs evaluation. Moreover, the
parallel analysis of different projects on the same study-area shows, in some cases, the absence of any coordination
among projects, as well as different outputs from the transport demand forecast model; this
creates problems in validating and comparing the results of each analysis.
After an introduction to the normative framework, the adopted methodology is presented. After that,
the paper – reflecting study objectives – includes first, an analysis of alternatives definition and tools used
for the decision support system; second, the discussion and comparison of the demand forecasts quality;
third, the approach used for the quantitative economic assessment. Then, as example, the standardised
railways operator procedure has been analysed and commented. Finally some conclusions will be drawn.
