The social sustainability of cycling: Assessing equity in the accessibility of bike-sharing services

Shared mobility solutions can respond to the social inclusion needs of communities, eliminating the costs of owning a private vehicle. In particular, bike-sharing services are an active mobility solution that especially favours sustainability since the bicycle is a transport mode with a low environmental impact and with positive effects on the health of users. However, the accessibility to shared services and the related travel opportunities may be conditioned by some spatial constraints, mainly due to the restrictions on the operational areas of such services.Based on this premise, this paper proposes a composite index of accessibility to bike-sharing systems to evaluate both the possibility for users to access the service and the potential destinations that can be reached, based on the availability of vehicles and the operational areas of the service. An evaluation of horizontal equity is conducted through the use of Lorenz curve and Gini index, two economic measures used to assess the distribution of a characteristic within the population. The approach was applied to the Dublin (Ireland) case study, where both a station-based service and a free-floating service are present.