Motor vehicles are separated into different classes for various statistical and regulatory purposes, typically based on gross vehicle weight rating (GVWR). GVWR is the maximum allowable total weight of a loaded vehicle. These classifications are important because they affect the availability of diesel vehicles in the United States and the standards those vehicles must meet.
Light-Duty Vehicles
The U.S. Environmental Protection Agency distinguishes between light- and medium/heavy-duty vehicles for the purposes of emissions regulations. All vehicles of less than 8,500 lb GVWR are considered light-duty vehicles and are subject to light-duty vehicle emissions regulations (in grams of emissions per mile). Passenger vehicles of 8,500 to 10,000 lb GVWR-primarily large sport utility vehicles and passenger vans-are also subject to light-duty vehicle emissions regulations.
Light-duty vehicles are also subject to Corporate Average Fuel Economy (CAFE) standards (in miles per gallon, mpg). These standards require each car manufacturer to achieve a specified sales-weighted fuel economy for its entire fleet of vehicles sold in the United States in each model year. In the future, CAFE standards will apply to all passenger and non-passenger vehicles up to 10,000-lb GVWR manufactured for U.S. sale.
Medium- and Heavy-Duty Vehicles
Engines for medium- and heavy-duty vehicles undergo separate emissions testing and certification (in grams of emissions per brake horsepower-hr, g/bhp-hr). Commercial vehicles of 8,500 to 10,000 lb GVWR are subject to medium-duty engine emission regulations.
For other regulatory and statistical purposes, vehicles are divided into eight classes based on GVWR. Medium-duty and "light heavy-duty" vehicles typically are defined as classes 3 to 6 (10,001 to 26,000 lb GVWR) and heavy-duty vehicles as classes 7 to 8 (greater than 26,000 lb GVWR). Source: Energy Efficiency and Renewable Energy, U.S. Department of Energy
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