Against the background of global warming, China faces the dual pressures of economic structural transformation and carbon emission reduction. While promoting economic development, the development and construction of transportation infrastructure has contributed to urban carbon emissions. Using an improved STIRPAT model, we examine panel data for 283 cities between 2003 and 2013 to explore the effects of transportation infrastructure on urban carbon emissions. The results show that transportation infrastructure increases urban carbon emissions and intensity. In addition, while the population scale effect of transportation infrastructure is conducive to decreasing carbon emissions, the economic growth and technological innovation effects of transportation infrastructure increase carbon emissions. Results also demonstrate that in large and medium-scale cities, construction of transportation infrastructure increases carbon emissions. In small cities, this relationship is not significant. Robustness tests support all findings. These results indicate that the effective development of carbon-abatement policies requires an examination of the effects of transportation infrastructure. (C) 2017 Elsevier Ltd. All rights reserved.