The aim of this report is to provide an analysis of potential benefits of a fleet of Shared Autonomous Vehicles (SAV) providing a taxi service to replace private car commuter trips in a metropolitan area. We develop a framework for dynamic allocation of SAVs to passenger trips, empty-vehicle routing and multi-criteria evaluation with regard to passenger waiting time, trip time and fleet size. Using a representation of current private trip demand for the Stockholm metropolitan area and a detailed road network representation, different scenarios (varying levels of accepted passenger waiting time at origin and accepted increase in travel time) are compared with respect to passenger travel time, number of vehicles needed and vehicle mileage. In a second step the environmental impacts of the different scenarios are assessed and compared using a life cycle approach. The assessment includes both a fleet consisting of currently in use gasoline and diesel cars as well as electrical cars. The results show that an SAV-based personal transport system has the potential to provide an on-demand door-to-door transport with a high level of service, using less than 10 % of today's private cars and parking places. In order to provide an environmental benefit and lower congestion an SAV-based personal transport system requires users to accept ride-sharing, allowing a maximum 30% increase of their travel time (15% on average) and a start time window of 10 minutes. In a scenario where users are not inclined to accept any reduced level of service, i.e. no ride-sharing and no delay, empty vehicle drive of an SAV-based personal transport system will lead to increased road traffic increasing environmental impacts and congestion. Envisioning a future using electrical cars a SAV-based system and electrical vehicle technology seems to be a “perfect” match that could definitely contribute to a sustainable transport system in Stockholm.