Environmental Impact Assessment of Vehicle Fleet Dynamics in a Medium Sized Mexican City
Liliana Fausto-Castro*, José Enrique Botello-Álvarez, Arturo Mandujano-Nava, Aideé Hernández-López, José Ramón Castellanos-Castro, Roberto Carlos Salmorán-Salgado and María Teresa Maldonado-Mancera
ABSTRACT
Urban expansion and accelerated industrialization have reinforced dependence on private automobiles, improving mobility but increasing air pollution and health risks, particularly due to the substantial proportion of obsolete vehicles still in circulation. This issue is especially relevant in medium sized cities undergoing rapid industrialization. A statistical assessment of the vehicle fleet of a medium sized Mexican city was conducted, analyzing CO₂ emissions by brand, vehicle type, and level of technological obsolescence using robust statistical methods and integrating technical specifications with local fuel consumption surveys to estimate annual emissions. Results indicate that 28% of vehicles are technologically obsolete; however, this segment generates nearly 55% of total CO₂ emissions. Significant differences were observed among brands: Brand 2 USA exhibited estimated emissions of 4.87 t CO₂/year, whereas the least polluting brand, Brand 1 ITA, emitted 2.37 t CO₂/year. Regarding vehicle type, sedans which account for 64% of the fleet produce 68% of total emissions, with an average of 5.04 t CO₂/year per vehicle. Hatchbacks demonstrated the best environmental performance, with 4.45 t CO₂/year. The disproportionate contribution of obsolete vehicles and high emitting brands high-lights the urgent need to implement targeted fleet modernization policies to reduce urban CO₂ emissions in medium sized cities.
