The BCIST economies have reinforced their identity as an emerging power in the fields of environmental technology and green transportation. The green transport sector undoubtedly plays an important role in green growth but also reduces CO2 emissions. The present study's objective is to examine the impact of transportation taxes on CO2 emissions in a comparative setting for BCIST economies in periods ranging from 1991 to 2019 by employing the nonlinear ARDL approach. The finding shows that transportation taxes are also a vital asymmetric determinant of CO2 emissions. An upsurge in transportation taxes lowers CO2 emissions in China, India, South Africa, and Turkey, while a decrease in transportation taxes intensifies carbon emissions in Brazil, China, and India in the long term. More transportation taxes limit CO2 emissions in South Africa as well as China in the short run. The findings of the study have some important economy-wise policy implications and permit a new direction for further research.