Shoppers are finding the same thing at dealerships across the country: a line of used cars and trucks that look fresh enough to be inside the showroom. They're only a year or two old, with good tires and the sheen of a recent wash and polish. More important for consumers, all the cars, though used, have been inspected and carry six-year, 100,000-mile, limited factory warranties.

Certified vehicles are part of a growing segment that some say could reshape the used-car business, according to the Dallas Morning News. Introduced by luxury automakers a decade ago, the certified-used concept has been adopted by virtually every mainstream manufacturer and is becoming a

third distinct category of vehicle, somewhere between new and used.

A typical used vehicle sold at a car dealership generates a gross profit of about $1,600, according to the National Automobile Dealers

Association (NADA). Theoretically, the grosses on certified used vehicles should be about $1,000 higher at around $2,600, according to the Dallas Morning News.