IMPROVING EMISSIONS ESTIMATES IN THE MEXICO CITY METROPOLITAN AREA

The serious air pollution problem in the Mexico City Metropolitan Area has led policy makers to ask what measures could be taken to improve air quality. There is data scarcity regarding transportation sources of air pollutants; current estimates of how much pollution is generated by transport are based on the assumption that traffic flows at an average speed of 32 kilometers per hour. This assumption is problematic because amounts of emissions of different pollutants vary with speeds. Therefore, it is important to know the actual traveling speeds on the road network, in order to get the best possible estimates of emissions. An urban transportation model was developed for the MCMA, to find congestion levels, travel times and emissions. Using available information from the 1994 Origin Destination Survey, as well as Census data, relevant parameters were found. Then these were used to model a future scenario for 2025. When speeds are close to 32 km/h, emissions are almost the same as when the 32 km/h average speed assumption is used. However, when travel speeds are low, emissions are underestimated. Because of the data scarcity problem during its construction, the model should not be used for policy analysis. Yet, it serves to underscore the importance of such a tool of analysis. KEY WORD: Urban transportation modeling, emissions estimates, travel demand 1. INTRODUCTIONi Transportation is a major source of air pollution in the Mexico City Metropolitan Area (MCMA)