Case Study: Mexico City’s Metrobús Bus Rapid Transit System

Metrobus photo

“Metrobús - Cidade do México, DF” © 2012 EMBARQ Brazil, used under a Creative Commons Attribution license.

Abt Associates performed a case study of Mexico City’s new Metrobús Bus Rapid Transit system to determine the health and economic benefits and values of PM2.5 emissions reductions. The transit system was developed by a partnership which includes: the Mexico City Government, the World Bank, CTS-Mexico, EMBARQ, the Global Environment Facility, CEIBA, the Shell Foundation, the Caterpillar Foundation, and the William and Flora Hewlett Foundation.


Planning for Mexico City’s Bus Rapid Transit system, known as Metrobús, began in 2002, and the system opened its first line in June of 2005. As of 2009, the two completed BRT lines spanned 50 km and 81 stations, with the Metrobús system utilizing a fleet of 226 buses carrying 475,000 passengers per day. Costs to date were $244 million including buses, or $163 million excluding buses (in 2010 US$, inflated from 2009 US$ using the U.S. Bureau of Labor Statistics CPI Inflation Calculator).

The new buses replaced hundreds of older and smaller buses that had previously traveled the two corridors. One source estimates that the first line of the project also resulted in a shift of 6% of traffic on Avenida Insurgentes from private vehicles to transit. Overall, Metrobús is responsible for estimated reduction of 80,000 tons of CO2 emissions per year.


The Metrobús project has also improved air quality in Mexico City. Large new buses meeting Euro 3 or better emissions standards replaced older dirtier buses and reduced the number of private car trips. According to Centro de Transporte Sustentable ( "Metrobus: A Winning Formula") and EMBARQ ("Mexico City – Metrobús: A Project That's Changed the City"), this resulted in an estimated reduction in fine particulate matter (PM2.5) emissions of 2.8 tons per year. Human exposure to PM2.5 is associated with premature mortality and other health effects. AirCounts™ can be used to estimate the benefits of avoiding premature deaths due to reductions in PM2.5.

Mexico City calculation example

Screenshot of AirCounts™ tool as used in this case study.


AirCounts™ estimates that the 2.8 ton reduction in PM2.5 in a given year would result in one premature death avoided. This reduction in mortality will occur during the 20-year period following the reduction in emissions. AirCounts™ estimates the present value of this human health benefit stream to be $1.8 million (in 2010 US$, at 3% discount rate).


These health benefits represent only 0.7% of total costs. However, they occur in perpetuity, whereas the cost represents a one-time cost. Moreover, the estimated health benefits of reductions in premature mortality represent only a fraction of the true benefits. There are other health benefits associated with reductions in PM2.5 (e.g., fewer heart attacks), as well as economic benefits, such as those associated with reduced commute times.

Mexico City continues to expand Metrobús, with two new lines spanning an additional 45 km already open since the estimates for these two lines were derived. These new lines are likely to drive further private traffic reductions and further lower PM2.5 levels.