Urban mobility is identified as one of the most CO2 emitters in France: transport represents 34% of CO2 emissions in France in 2006 (ADEME 2006), including 25% of urban trip emissions. Some previous studies compare transport modes (Finkbeiner & Al. 2006), or assess CO2 emissions that are related to urban mobility on a real case (INSEE 2011). But literature is lacking about multi-criteria analysis of urban mobility in the general case. In particular, Life Cycle Assessment has not been largely used to qualify urban mobility impacts despite its possibility to evaluate the environmental impact (ISO14040, 2006). Nevertheless, the complexity of the system "urban mobility"is a first difficulty to the evaluation, especially concerning the definition of goal and scope. The main topic of this poster is to find out a way to complete and adapt LCA in order to enable the evaluation of a complex system under the case study of urban mobility. We propose an approach based on the System Analysis Design Technique (SADT) that allows a clear and complete definition of the "urban mobility"system. Then the possibility to include more societal indicators beyond the environmental ones (such as noise, satisfaction of consumers, time travel, costs etc) will be studied. The final aim is to provide a configurable dynamic system to evaluate different scenarios of urban mobility. The first results consist of a complete definition of the system that is based on a segmentation of urban mobility into sub-systems that constitute the "goal and objectives"step in LCA. This decomposition prepares to the next step of LCA, in which modal splits will be aggregated with elementary assessments of modes to obtain a multi-criteria analysis for several scenarios.