The Carbon Gap in Everyday Mobility: Accessibility Benchmarks and Mobile Phone Evidence

Achieving carbon neutrality in personal mobility is dependent on technological improvements as well as considerable behavioural changes to reduce overall travel volumes and distances. However, implementing policies that aim to change behaviours also bear the risk of creating (more) inequalities. This paper proposes a combination of a new accessibility indicator with monitoring by mobile phone data analysis to accelerate and steer carbon reduction in transport. Minimum Mobility Standards (MMS) are a recently introduced accessibility indicator that defines the minimum carbon emissions required at a location to ensure access to essential daily activities. A comparison of these theoretical minimums with actual travel behaviour, as inferred from anonymised mobile phone data (MPD), and an estimation of transport modes and related CO2 emissions, reveals whether local policies should focus on steering behaviour change or improving accessibility to activities to enable change at first. The findings emphasise the potential for targeted policy interventions to further reduce emissions, particularly in medium-density zones where overshoot is most evident. Recommendations are provided for differentiated strategies based on urban form and population density.