Urban Transport Pollution: Revisiting the Environmental Kuznets Curve

An inverted-U relationship between GDP per capita and three urban transport-related emissions is tested (using data from 84 cities). Per capita urban transport-related emissions of CO, VHC, and NOx increase and then decline at observed income levels—a result driven by a similar inverted-U relationship between income and emissions technology (i.e., emissions per passenger-km). However, for urban transport energy consumed, the estimated turning point was well beyond the sample bounds. Passenger-km per capita and car ownership both rise, and public transport’s share of those passenger-km falls monotonically with income