Can the co-existence of bike, e-scooter, and car-sharing promote sustainable mode choices?

• Mode choice modelling among three shared modes and four “traditional” modes. • Comparative mode choice analysis across three cities: Brussels, Munich, and Vienna. • Stronger modal shift towards car and bike sharing compared to e-scooter sharing. • Shared mobility competes with public transport, but also promotes it. • Higher value of travel time for shared modes than public transport. The introduction of shared mobility systems has received attention as a potential measure to reduce private car use and tackle the environmental and social externalities of urban mobility. This research investigates travel mode choice behaviour in the context of the co-existence of three emerging shared modes (car, bike, and e-scooter sharing) with four so-called “conventional” modes (walking, public transport, private bikes, and private cars). Based on data collected via an online survey, including a stated preference mode choice experiment pivoted on real-life trips, of residents ( N = 1448) of three European cities (Vienna, Brussels, and Munich) the study offers insights into mode substitution and its determinants. The analyses revealed that car and bike sharing have the highest potential to replace trips by private cars and public transport, respectively. Interestingly, despite the competition between shared modes and public transport, the introduction of shared mobility services could also enhance the attractiveness of public transport via a decoy effect. These findings suggest that shared mobility systems could have a broader positive effect on the modal split of sustainable mobility services. The results of discrete choice models point out that interest in shared mobility varies across individuals with different sociodemographic characteristics and mobility habits, suggesting that although shared mobility can reduce some mobility gaps, its contribution to overall mobility equity needs further investigation. The study output highlights that while the presence of multiple shared mobility services could bring some social and environmental sustainability benefits, there are also limitations in their potential to advance current conditions.