Launched in June 2011, in an initial group of four Latin American cities — Bogota, Curitiba, Rio de Janeiro, and Sao Paulo — this innovative program seeks to reduce the carbon footprint of public transportation in Latin America and develop a market for fuel efficient, low-carbon buses in the region. Supported by the Inter-American Development Bank (IADB), the program brings together cities, bus technology companies, and local transport operators to test bus technology performance in city-specific driving conditions and duty cycles. Through the publication of results, it establishes the case for investment in hybrid and electric buses. Ultimately, the program aims to catalyze the deployment of up to 9,000 buses across Latin American cities over the next five years, with steady-state reduction of annual CO2 emissions by 475,000 tons. Bus testing has so far been conducted in Rio de Janeiro and Sao Paulo, and focused on comparing hybrid diesel-electric technology to conventional diesel technology. Results measured a range of factors from exhaust emissions to energy performance, following a rigorous test protocol based on simulating real-world driving conditions. Promising findings show that hybrid technology is more fuel efficient and produces fewer local air pollutants and greenhouse gases than conventional diesel buses. New campaigns will run across all four cities, with a final report released by October 2012. Thereafter, program expansion, including a focus on market development strategies and the possible addition of new cities, will get underway.