The hidden dimension of low-carbon public transport policies: From biodiversity conservation to user preferences

Transport infrastructures dedicated to low-carbon public transport are seen as a central tool in public policy strategies to mitigate climate change. Yet, the development of transport infrastructures has significant direct and indirect negative effects on biodiversity and social acceptability of these impacts remain little assessed. In this study, we analyse potential impacts of 20 tramway existing projects in France and social preferences with regard to their ecological and landscape integration. Using a discrete choice experiment on 1000 respondents, we show that users, even the most time constrained, are accepting an average travel time lengthening of 15 %, if tramway project integration retains a more wooded landscape, more diverse and abundant species and access to a natural area. We show that brief information provided on the state of biodiversity through framing encourages environmental consideration. We quantify the estimated impact of these projects on the naturalness of habitats and the buffer effect that project ecological integration could allow. These results highlight the non-negligible ecological impact of low-carbon transport infrastructures. They underline the need to consider climate change mitigation strategies in tandem with biodiversity preservation, while taking into account user preferences which affect the acceptability of the ecological and landscape integration of these projects.