This article examines Bus Rapid Transit (BRT) as a near-term strategy for reducing CO2 emissions in a typical medium-sized U.S. city. The paper compares the expected CO2 emissions from three scenarios to meet the city's growth in work trips by 2011: a no-build option that relies upon private automobiles and a diesel bus fleet; building a light rail (LRT) system; and building a BRT system using 40-ft or 60-ft low emission