Multimodality and Sustainable Transport: A Critical Perspective

Abstract

Sustainable transport research and policy making currently identify multimodality as an important way to reduce carbon emissions and other negative transport externalities. This emphasis is consistent with the ‘behaviour change agenda’ for sustainable mobility, which places responsibility for changing behaviour on ‘citizen-consumers’, while policy makers help them make ‘better’ modal choices, rather than introducing regulatory or pricing measures. In this paper, we present findings based on the British National Travel Survey, which lead us to qualify the emphasis currently placed on multimodality. We first focus on the relationship between multimodality and CO₂ emissions, at the individual and trip level. While multimodal trips produce less CO₂ than unimodal trips over comparable distances, they are typically longer and therefore have higher average emissions. At the individual level, there is an association between greater multimodality and lower emissions, although of weak magnitude. Second, we investigate trends in multimodality between 1995 and 2015. Contrary to expectations, we find that individual-level multimodality has decreased over time, notably among younger adults, and this during a period of declining car travel distances per capita. We conclude that there is merit in encouraging greater multimodality, but this can hardly be the only or primary goal of sustainable transport policies. More policy attention needs to be directed to the pivotal role of high levels of travel activity, and the reduction of these.