Bibb v. Navajo Freight Lines, Inc.
Bibb v. Navajo Freight Lines, Inc., 359 U.S. 520 (1959), is a United States Supreme Court case in which the Court held that the Illinois law requiring trucks to have unique mudguards was unconstitutional under the Commerce clause. Background The state of Illinois enacted a statute requiring curved mud guards, instead of straight mudflaps on trucks driven in Illinois. Although there was no federal regulation requiring mudflaps or mudguards, Arkansas required straight mudflaps, which were legal in at least 45 states. The Illinois legislature asserted that the unique curved mudguards would be more useful in preventing stones and other debris to be kicked up from the back of trucks, thus preventing more accidents than other types of mudflaps. The plaintiffs were trucking companies who drove through Illinois and would have to use one form of mudflap equipment while in Illinois, but other mudflap equipment while in other states. The named plaintiff was Navajo Freight Lines, Inc., of New Mexico. The only issue was whether in the absence of federal regulation, in this context did the Commerce Clause allow one State to prescribe standards that would affect interstate carriers in a way that would conflict with the standards of another State.