South Carolina State Highway Dept. v. Barnwell Bros., Inc.

South Carolina passed a regulation restricting the width and weight of trucks, including semi-trailer trucks treated as a single unit for weight purposes, operating on its state highways; Barnwell Bros. (plaintiff), an out-of-state trucking company, sued South Carolina's highway department (defendant), challenging the weight restrictions as an impermissible burden on interstate commerce. The district court upheld the regulation since Congress hadn't acted in this area, but the court of appeals reversed, and South Carolina appealed to the U.S. Supreme Court.