The transportation sector has significantly contributed to greenhouse gas and air pollutant emissions. Based on the Kaya constant equation and the LMDI decomposition model, A synergistic reduction effect model of transportation tailpipe Environmental negative externalities emissions is constructed to adopt the inter-provincial panel data of China from 2005 to 2019. The synergistic reduction emission impact and indirect drivers between air pollution and carbon emission are analyzed. The results show that the drivers of the synergistic impact are mainly energy efficiency and industrial structure. Significant synergistic emission reduction effects exist in eastern China, western China, medium-sized transportation markets, and less developed tourism regions. Further, increasing environmental regulation can improve the synergistic reduction impact of the transportation sector's air pollutants and carbon emissions. This paper provides theoretical support for winning the battle of pollution prevention and control and achieving the "dual carbon" goal in the new era.