Public Transport Emissions and Economic Growth in South Africa: Evidence from a Dynamic STIRPAT–BCMM Framework

Abstract

South Africa’s transport sector remains a major contributor to greenhouse gas emissions, yet limited empirical evidence exists on the environmental drivers of public transport emissions at the provincial level. This study applies an extended Stochastic Impacts by Regression on Population, Affluence, and Technology (STIRPAT) framework within a dynamic panel setting to examine the determinants of provincial public transport emissions across nine South African provinces from 2015 to 2022. Rather than conducting economy-wide emissions accounting, the analysis focuses on transport-specific drivers relevant to public passenger mobility, including population, income, fuel consumption, infrastructure investment, and modal usage. A Bias-Corrected Method of Moments (BCMM) estimator is employed to address emission persistence, endogeneity, and small-sample bias, with pooled ordinary least squares and fixed-effects models used for robustness. Province fixed effects are used to control for unobserved regional heterogeneity, while common dynamic elasticities are estimated for key influencing factors. The results reveal strong dependence on emissions, indicating substantial structural persistence over time. GDP per capita emerges as the dominant and statistically significant driver of public transport emissions, while population, urbanisation, fuel consumption, transport infrastructure investment, and modal usage (road and rail) are statistically insignificant once dynamics and unobserved heterogeneity are controlled. These findings suggest that public transport emissions in South Africa are driven primarily by economic growth and entrenched structural factors rather than short-run changes in transport systems. Policy implications highlight the need for sustained low-carbon investment, technological transition, and integrated transport planning to decouple economic growth from emissions and support progress toward Sustainable Development Goals 11 and 13.