Models and methods for transport demand and decarbonisation: a review

Abstract

Rising global greenhouse gas emissions from the transport sector pose a major challenge to meeting the targets of the Paris Agreement. This raises questions of how technology, infrastructure and societal trends and policies can influence transport demand and thus also emissions, energy demand and service levels. Here the literature on factors relevant to shifting total transport activity and mode shares, categorised into exogenous drivers, socio-behavioural, infrastructural and technological aspects, is reviewed. For each factor, current approaches to modelling and measuring the impact of each factor on transport systems are summarised, resulting in a proposed taxonomy to classify transport demand modelling approaches. We then comment on the suitability and sufficiency of existing modelling approaches for representing scenarios consistent with the Paris Agreement targets in models of the entire global energy system. Factors that affect transport demand are currently insufficiently represented in integrated assessment modelling approaches and thus emission reduction pathways. Improving the comprehension and representation of diverse factors that affect transport demand in global energy systems models, by incorporating features of complementary models with high resolution representations of transport, holds promise for generating well informed policy recommendations. Accordingly, policies could influence the development of the factors themselves and their potential role in mitigating climate change.