[en] With recent surge in the number of vehicles, particularly private vehicles, the transport sector has significantly contributed to the increase in energy consumption and carbon dioxide emissions in China. Most of the existing researches utilized time series data to investigate the factors influencing transport sector's carbon dioxide emission at the national level while neglecting the level of regional differences. This paper adopts provincial panel data from 2000 to 2012 and panel data models to examine the key driving forces of carbon dioxide emissions in the transport sector at the regional level in China. The estimation results show that the impacts of urbanization on carbon dioxide emissions in the transport sector vary across regions and decline continuously from the western region to the eastern and central regions. Private vehicles are more important than cargo turnover in emission reduction because of its relatively inefficient and excessive growth. The role of energy efficiency improvement in mitigating carbon dioxide emissions in the three regions varies due to significant differences in research and development investment and management efficiency. Hence, in order to effectively achieve emission reduction, local governments should consider all these factors as well as regional heterogeneity in developing appropriate mitigation policies. - Highlights: • The factors of carbon dioxide emissions in China's transport sector were explored. • The impact of urbanization on carbon dioxide emissions varies across regions. • Private vehicles are more critical than cargo turnover in emission reduction. • The role of energy efficiency in the three regions is exactly the opposite.