This paper analyses the impact of an energy efficiency program for light vehicles in Brazil on emissions of carbon dioxide (CO2), the main greenhouse gas in the atmosphere. Several energy efficiency programs for light vehicles around the world are reviewed. The cases of Japan and Europe were selected for presentation here given their status as current and future world leaders in the control of passenger vehicle fuel consumption. The launching of the National Climate Change Plan and the pressure on the Brazilian car industry due to the world financial crisis make it a good time for the Brazilian government to implement such a program, and its various benefits are highlighted in this study. Three scenarios are established for Brazil covering the 2000-2030 period: the first with no efficiency goals, the second with the Japanese goals applied with a 10 years delay, and the third, with the Japanese goals applied with no delay. The consequences of a vehicular efficiency program and its middle and long-term effects on the consumption of energy and the CO2 emissions are quantified and discussed. The simulation results indicate that efficiency goals may make an important contribution to reducing vehicular emissions and fuel consumption in Brazil, compared to a baseline scenario. (C) 2009 Elsevier Ltd. All rights reserved.