The objective of this study is to set a methodology for transportation systems evaluation using an approach different than the traditional. The first part consist on a description of the transportation problem, the different concerns over the years and how transportation planning faced it. The second part explains the systems point of view, that considers problems as part of a bigger ones and relate them through causal relationships that make possible to incorporate social and environmental impacts to the model. Then a description of the traditional approach for transportation systems evaluation is given as a background for the dynamic economic evaluation that allows the planner to see the evolution of the parameters over time. The methodology is applied to a scenario where a new transportation facility is going to be built and the best of the alternatives should be selected. This study also emphasizes that the methodology is a tool for the decision-maker but it will never replace his judgment. / M.S.