Interstate Commerce: Constitutionality of State Weight and Size Limitations as Applied to Interstate Motor Carriers

A South Carolina statute limited the width of motor trucks (including semi-trailers) to 90 inches and their gross weight to 20,000 pounds. The validity of this legislation was challenged before a three-judge federal court on three grounds: (1) that it was a denial of due process under the Fourteenth Amendment; (2) that the power of the states to regulate size and weight of motor vehicles used in interstate commerce had been superseded by the Federal Motor Carrier Act of 1935; (3) that the statute as applied to vehicles used by interstate motor carriers placed an unreasonable burden upon interstate commerce. The three-judge court declared the statute valid in so far as the first two grounds of attack were concerned, but as to the third held that the statute placed an unreasonable burden upon interstate commerce and enjoined enforcement thereof as to interstate carriers. An appeal was taken by the South Carolina Highway Department. Held, the decree of the three-judge court should be reversed since the limitations adopted were not so unreasonable as to constitute an unlawful burden upon interstate commerce. South Carolina Highway Dept. v. Barnwell Bros., (U.S. 1938) 58 S. Ct. 510.