Carbon Dioxide Reduction Benefits of Bus Rapid Transit Systems

Appraisal of the greenhouse gas (GHG) impacts of transportation system interventions, such as investments in bus rapid transit (BRT), is of growing interest to transportation and environmental officials, investors, and other stakeholders. The lack of an accepted methodology to estimate the carbon dioxide (CO2) mitigation potential from modal shift and reductions in vehicle kilometers traveled has inhibited access to GHGrelated funding mechanisms. This paper focuses only on development of a common methodology for BRT projects with sufficient information to conduct analysis. Adjustment factors were postulated that might be used to estimate generalized BRT investment impacts in large, developing cities. Parameters were established on the basis of in-depth analyses of the CO2 impacts on three BRT systems: those in Bogotá, Colombia; Mexico City, Mexico; and Jakarta, Indonesia. An analysis of CO2 emission reductions related to the Bogotá BRT system secured Clean Development Mechanism certification for carbon financing in 2006 and followed a corridor-focused methodology. In 2007 to 2008, a regional, integrated transportation-land use model was applied to BRT scenarios for Mexico City. Calculations have been updated on the basis of data from post-implementation passenger surveys. The methodology does not capture some potential sources of emissions savings, such as fuel consumption internal to the bus system. But even accounting for these differences, the Jakarta BRT system could produce much smaller GHG benefits. This paper reports on a preliminary effort to develop a reasonable methodology to estimate CO2 abatement potential at the project level in a way that facilitates aggregation at the national and regional levels