Can Carsharing Reduce Car Ownership and Emissions? An Analysis Based on an Intermediate Modelling Approach

Abstract

AbstractAs cities grow larger, they often struggle in finding sustainable and liveable mobility solutions to accommodate this growth. Many alternative modes of transport—such as public transport, carsharing systems, bikesharing systems—exist next to private car travel. The effects of expanding those alternatives are often challenging to model. This is in particular the case for small and medium sized cities, which often use straightforward and easy-to-use four-step traffic models. The alternative modes of transport could be modelled using extensive agent-based traffic models. However, these are expensive to make and require a lot of data and expertise. In the context of the EU H2020 project “MOMENTUM”, we developed an intermediate modelling approach that aims to reconcile the user-friendliness of four-step traffic models with the predictive power of agent-based models to investigate the effects of alternative modes of transport. In this paper, we demonstrate the modelling of a policy plan—away from private transport towards durable modes of transport such as shared mobility and public transport—in the city of Leuven, Belgium. We focus particularly on the developed disaggregate car-ownership model, induced demand model, and link-level emission model. It was found that an improved carsharing supply can significantly reduce the car ownership of a city’s households. The largest reduction is seen in households that own several cars and decide they can do with one fewer. These households can use the carsharing system for the occasional trip they would make with the additional car. Moreover, policy measures for the promotion of alternative modes of transport—which might increase the travel times to reach the city for privately owned cars—were found to be able to reduce the city’s mobility-related emissions. In conclusion, we demonstrated that the developed intermediate modelling approach is versatile and applicable to the cities like Leuven, such that they can also account for new modes of transport. The developed models and concepts can help other small- and medium-sized cities to shape their mobility plans.KeywordsShared mobilityTravel demand modellingTransportation planningCarsharingTransport emissions modellingCar ownership modelling