Motorised mobility has increased in a significant way in last years, and this has brought too much congestion in urban areas. This situation has deteriorated city centres’ liveable conditions. Therefore, urban areas need effective and flexible transport systems in order to develop policies integrating the three aspects of sustainability: economy, society and environment. Current situation in urban areas could be described by the cycle of urban decline. The choice of travelling by car produces more traffic jams, thus reducing the efficiency of public transport and the quality of live in urban districts by increasing pollution and accidents levels. Firms decide to move out to suburban areas where the provision of public transport is very low, and again people decide to travel by car, producing the vicious circle. In short, growing car traffic in urban areas makes necessary to cut this vicious circle by providing new public transport infrastructures. But, what kind of public transport infrastructures? In many cities, rail urban projects (tram, metro and light rail systems) appear as the optimal solution in getting a sustainable mobility for the growing urban population, because they provide a modern image of the city among other benefits: fast, regular, safe and comfortable services, with medium-high capacity. Nevertheless, these kind of projects require large investments in order to be implemented, mainly in infrastructure construction and maintenance costs. These investments are much higher than for implementing solutions based on alternative transport modes, for example, a new bus line. Therefore, the financial profitability of the rail transport investments is very low. However there exist other not economic benefits –social benefits and environmental improvements- induced by such rail projects. Therefore, it is required to develop an ex-post evaluation considering economic, social and environmental effects in order to find the real benefit provided by these projects and to justify these large investments. This evaluation procedure has been developed in the framework of a V FP European project called TranSEcon (Urban Transport and Socio-economic Development). The methodology is based on a multicriteria analysis which considers a number of criteria to achieve the global objective of sustainability. (Author/publisher)
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