Transporting people and goods accounts for 1.8 trillion tons, or 27 percent, of U.S. greenhouse gas (GHG) emissions and approximately 70 percent of all U.S. oil use (or about 13.1 million barrels of oil per day, excluding biofuels). With the burning of gasoline and diesel accounting for 59 percent and 24 percent of the transportation sector's emissions, respectively, significant reductions in auto and truck emissions are essential to climate change mitigation efforts. Medium and heavy-duty vehicles, powered by diesel fuel, represent only 5 percent of the vehicles on the road but currently account for more than 20 percent of transportation emissions, as trucks are typically driven much greater distances than cars. Therefore, while auto standards are important because of the volume of vehicles on the road, truck standards are just as important because increasing the efficiency of one truck has a much greater impact than increasing the efficiency of a single car. The National Highway Transportation Safety Administration (NHTSA) and the Environmental Protection Agency (EPA) have estimated that the standards listed in the timeline below will save consumers over $1.9 trillion at the pump, reduce oil consumption by 14.3 billion barrels, and eliminate 7.3 billion metric tons of GHG pollution by 2027. The benefits of the light-duty vehicle standards alone are the equivalent of reducing gas prices by $1 per gallon, cutting OPEC oil imports in half, and reducing emissions by more than the total amount U.S. CO2 emissions in 2014. This fact sheet will provide a timeline of federal fuel efficiency actions under the Energy Independence and Security Act of 2007, and the anticipated benefits of these measures.