Carbon Dioxide Emissions from Urban Road Transport in Latin America: CO2 Reduction as a Co-Benefit of Transport Strategies

Abstract

We review aggregate trends in CO2 emissions from road transport in Latin America. Comparison with other regions, as well as with automobile ownership and use suggests that road transport the emissions in this region are closely connected to high automobile ownership and use. Examination of detailed estimates of vehicle stocks, use and fuel intensity as well as data from four large metropolises in the region confirms this suggestion. The same data show that it is cars that are the main reason for congestion, high levels of air pollution, and other transport related externalities in urban regions. Thus mitigation of CO2 emissions from urban transport means dealing directly with cars and car use. Widely cited projections of car ownership and use in 2030 suggest that car use will more than triple. Even with a 20{%} reduction in fuel use and emissions/km, CO2 emissions will be well above present levels. But if the fundamental problems of urban transport that plague Latin America today are addressed, car use will grow by considerably less, restraining CO2 emissions considerably as a co-benefit of transport strategies. A review of the impact of a BRT project in Mexico City shows a reduction of 10{%} in traffic-related emissions in the BRT corridor even without fuel and emissions being addressed directly. One third of those savings arose because Metrobus riders left cars at home and took the bus. The monetized value of the CO2 externality is small compared to other benefits of Metrobus as a transport project. Thus CO2 reduction can be evaluated as a co-benefit of a transport project. Confronting other large transport externalities such as congestion would likely lead to reductions in car use and greater use of other modes. Thus we argue that CO2 should be treated as a symptom of transport problems, particularly high rates of car use. Doing this may offer significant restraint in CO2 emissions at little or no ``cost'' of saved CO2.