Impact assessment of road fleet transitions on emissions: The case study of a medium European size country

by  T. Fontes and S. R. Pereira

Fontes, T. and Pereira, S. R. (2014). Impact assessment of road fleet transitions on emissions: The case study of a medium European size country. Energy Policy, 72: 175–185.

This paper aims to examine the impacts of fleet composition changes on emission due to the introduction of different road transportation policies in a medium size European country (Portugal) applying an ex-post analysis (e.g. policies based on fuel pricing, car scraping, car taxation). A baseline scenario was compared with a counterfactual scenario in order to understand what would occur in the absence of the introduction of those policies. For each scenario, four approaches were assessed using economic effects and/or human health costs. HC, CO, NO_x, PM and CO₂ emissions from passenger cars and light duty vehicles were evaluated. The results show high statistical significance (p≤0.05) between CO emissions and different vehicle features as vehicle age, fuel type and engine classes. The same pattern was observed between the average vehicle age and HC, NO_x and PM. After the implementation of road traffic policies, the average emission factors of the fleet decreased 28–62% for HC, CO, NO_x, PM and 20–39% for CO₂. However, if a counterfactual scenario would be implemented, the reduction would be 20–80% and 26–55% higher, respectively. The results demonstrates that although were recorded some benefits, the fleet characteristics distribution were more environmental friendly in 2001 than in 2011.