The project began with an inventory of existing car sharing systems (CS) in Europe. All CS operators active in the Europe at the end of 2017 have been individuated using a desktop research. In addition, CS systems in 20 cities were thoroughly investigated to uncover their operational characteristics, their users and the journeys these users make. This allowed to depict the likely evolution of CS in the absence of major policy actions, thus defining the business as usual scenario.Desktop research data were used to carry out a multidimensional classification of CS services with a bottom-up approach, that considered service operational characteristics, vehicles type, pricing, subscription fee. This resulted in six different profiles of CS systems that were validated by a group of international experts. Such profiles are unevenly distributed around Europe: while most roundtrip station-based CS services were found in Western Europe and many peer-to-peer services in Northern Europe, free-floating services were concentrated in Southern Europe and were quickly growing in the Eastern Europe.The second step was to understand the influence of CS on the wider automotive market and industry. CS is still embryonic, an evolving entity within the automotive industry that is also rapidly changing. The future for CS is more significant than its market shares, because both the existing automotive industry and disruptive new entrants are searching for the right ‘formula’ of revenue streams in the transition to the automobility of the future. The third step was to investigate the influence of individual, social, political, environmental and economic variables in driving the behavioural change towards shared mobility by comparing CS users and non-users. How people perceive the usefulness of CS for their routines (self-efficacy) and a social network that approves and has positive attitudes towards CS (subjective norms) were identified as main predictors of CS usage. Different profiles of car sharing users and non-users have been identified.Mobility styles and CS cultures in uptake European cities were discussed in a workshop at the CIVITAS Forum 2018 in Umea (Sweden). The outcomes were presented and validated within a CS experts workshop hosted by the city of Bremen in January 2019. The project clarified how CS impacts on personal long-term mobility choices and how these changes are influencing the use of different travel modes and everyday mobility decisions: CS members tend to own fewer cars, more public transport passes and bike-sharing membership than non-members. Consequently, CS members are more multimodal. Among CS users however, differences can be found according to the variants they are registered for. Round trip services have a much deeper impact in decreasing car ownership that free-floating, but the latter are more appealing for larger population segments.There seems to be a trade-off between the market penetration of a service and its impact in terms of car ownership changes for its customers, thus the aggregate impacts of different schemes could be of the same order of magnitude. Since different variants did not appear in competition, a policy indication emerging from STARS is to promote both as much as possible.Modal switch models applied in trip-level analyses showed that free-floating CS has the potential to cover up to almost 10% of the daily travel demand, when appropriately leveraging both the CS and private car costs (rupture scenario). The potential impact of CS on the automotive sector is still marginal. CS is too small and polarized in medium-large cities to have an impact on new passenger car sales. In this scenario, the automotive sector should modify its strategy, not only investing in CS fleets, but also considering federative solutions in which several “mobility providers” join to satisfy the users requests. Recent withdrawal/downfall of some services in North America and Europe rose questions about the robustness and profitability of free-floating CS if not well integrated in larger mobility solutions or properly integrated in OEMs’ core business. On the other hand, recent merges might indicate consolidation and a certain maturation of the market. Public-Private-Partnership are still rare, but seem a possible and win-win solution.The final project output is a toolbox that provides essential key results to decision-makers to understand the different forms of CS and their effects. All results were prepared in a compact and clear form such that decision-makers can find the relevant decision criteria for their respective. The drafted toolbox was tested and enriched with the feedbacks from different stakeholders during the workshop held along the STARS final conference in Bremen.