In the 1970s, the mid-size vehicles most often had wheelbases between 112 inches and 118 inches. A defining moment happened in the late 1970s, when rising fuel expenses and government mileage control regulations brought about shrinking auto size classes. Automakers began moving "full-size" nameplates to smaller platforms. The EPA presented new "official" size U.S. designations, which defined sizes passenger and cargo room. Formerly mid sized autos that were based on the same platform, such as to the AMC Matador vehicle, featured a combined passenger and cargo volume containing 130 cubic feet, and were suddenly viewed as "full-size" automobiles.
Mid-size size vehicles today for the most part offer wheelbases between 105 inches and 110 inches. Another generally utilized definition is that of the EPA, which classifies autos offering between 110 cubic feet and 119 cubic feet of inside volume as being mid-size.
During 2012, mid-size autos were the most popular vehicle category sold in the United States
GM delivered innovations such as
unibody construction, independent front suspension, and a single-piece steel roof, GM pushed the envelope by designing a succession of vehicles which included the Chevrolet Corvette, 1949 Buick Roadmaster, and Chevy BelAir, plus the Cadillac El Dorado in 1959. GM built cars were every bit as fun to drive off in as they were watching drive by.
During World War II GM delivered more products to the Allies than any other automobile company. Former President of GM, William Knudsen was selected in 1940 by President Roosevelt to Chair of the Wartime Office of Production Management and by 1942, GM was 100 percent in production with their Allied war support. GM provided over $12 billion in materials including trucks, airplanes and tanks.