Light-duty vehicles have less than an 8,500-lb gross vehicle weight rating (GVWR). They include sedans, pickup trucks, high-performance sports cars, sport-utility vehicles, and passenger vans. Gasoline-powered vehicles dominate this class in the United States. However, more light-duty diesel vehicles are becoming available as state-of-the-art "clean diesel" technologies enable them to meet the same stringent emissions regulations as gasoline vehicles. The high fuel economy of light-duty diesel vehicles makes them attractive to consumers.

Biodiesel

Although light-duty diesel vehicles are not technically "alternative fuel vehicles," they can run on biodiesel, an alternative fuel under the Energy Policy Act of 1992. Biodiesel, which is mainly used as a blend, can be used in most light-duty diesel vehicles with no engine modification. The most common biodiesel blend is B20, which is 20% biodiesel and 80% conventional diesel. B5 (5% biodiesel, 95% diesel) is also commonly used in fleets. To learn more about this fuel, go to the Biodiesel section. 

Emissions

Currently, most light-duty diesel vehicles are equipped with oxidation catalysts that reduce carbon monoxide (CO) and hydrocarbon (HC) emissions, and many have particulate matter (PM) traps that reduce PM emissions as well as CO and HC emissions. In combination, these devices can decrease emissions of CO by 80%, HC by 90%, and PM by 98%. New emissions control devices soon will be required to meet stringent emissions standards. Learn more about diesel emissions and how technologies such as selective catalytic reduction, Diesel Exhaust Fluid, and NOx adsorbers are controlling them.

Clean Diesel

Ultra-low sulfur diesel (ULSD)—which is called "clean diesel" when used in conjunction with advanced emission control devices—is available at fueling stations nationwide and can be used in any diesel vehicle. This fuel reduces the sulfur content in diesel fuel by 97%. Europe has used ULSD for several years. The United States began its changeover to ULSD in June 2006, after the U.S. Environmental Protection Agency (EPA) mandated that 80% of highway diesel fuel produced or imported contain 15 ppm or less sulfur.

The Federal Alternative Fuel Vehicle Tax Credit provision of EPAct 2005 includes a tax credit for lean-burn diesel vehicles. The credit is sometimes referred to as the Clean Diesel Tax Credit and is effective January 1, 2006; however, no 2006 or 2007 diesel vehicles met the emissions requirements for credit. No 2008 vehicles have been certified as qualifying for the credit. Diesel vehicles up to 6,000 lb GVWR that meet EPA Tier II Bin 5 emissions requirements will be eligible for the credit. Diesel vehicles of 6,001 to 8,500 lb GVWR must meet Tier II Bin 8 requirements. Manufacturers will certify with the EPA that their vehicles meet the emissions requirements. The IRS must then issue a notice that the vehicle qualifies for the tax credit before consumers or commercial businesses can claim the credit. There are other IRS requirements to claim the credit.