The need for needs: Transport modelling and planning for sufficiency

This is the authors' abstract. We don't add key points for this paper.

Transport planning and modelling must consider ecological impacts and social justice to address the grand challenges of the 21st century. Ecological and social dimensions are central to the concept of sufficiency, but dominant methods in transport modelling and practice do not consider them explicitly. Instead, common transport models are based on individual utility maximisation under the assumption of unconstrained energy and material consumption. We review recent advances literature related to human need satisfaction as a novel approach to tackle growth dependency in transport. We first elaborate on useful foundational concepts to define needs and thresholds corresponding to sufficient levels of access to essential services and mobility, and approaches to acknowledging the constraints of planetary boundaries. We highlight promising approaches for measuring mobility need impairment, satisfaction and essentiality, and connect them to advances in disaggregated transport modelling. Concerning ecological impacts, we outline how these results can be useful for sustainability analysis in global-level aggregated models, which then inform planning on upper sufficiency boundaries. Measures of need satisfaction and environmental outcomes should ultimately inform novel methods for transport and infrastructure planning, as well as appraisal and policy frameworks. Our result is a framing of mobility needs as an operationalisation of sufficiency concepts in mobility that relies on individual- or household-level need satisfaction and impairment as well as societal-level threshold assessment. We draw conclusions for empirical research and modelling, highlight where participatory research is mandatory, and conclude with an inter- and trans-disciplinary future research towards needs-based design of mobility provisioning systems.