Air emissions impacts of modal diversion patterns induced by one-way car sharing: A case study from the city of Turin

This paper aims to understand to which extent the spread of one-way car sharing in an urban area can contribute to limit air pollutants and greenhouse gas emissions by diverting trips from existing travel means. Modal switch models informed the definition of five mobility scenarios in the city of Turin (Italy). Related emissions were quantified to understand how to maximise the positive environmental impacts of car sharing. Models’ results indicate that the car sharing modal share might increase up to a maximum of 10%. The diverted travel demand is mainly subtracted from private cars, however environmental benefits are partially offset by switches from public transport and active modes. The planning scenario would lead to a reduction of the externalities related to the emissions produced by the whole transport system of 1% in terms of social costs. Such benefits can be increased up to 3.6% by promoting electric car sharing fleets.