William O. Douglas

“ An order of the Arkansas Commerce Commission, already mentioned, [6] requires that trailers operating in that State be equipped with straight or conventional mudflaps. Vehicles equipped to meet the standards of the Illinois statute would not comply with Arkansas standards, and vice versa. Thus if a trailer is to be operated in both States, mudguards would have to be interchanged, causing a significant delay in an operation where prompt movement may be of the essence. It was found that from two to four hours of labor are required to install or remove a contour mudguard. ”

“ The matter of safety was said to be one essentially for the legislative judgment; and the burden of redesigning or replacing equipment was said to be a proper price to exact from interstate and intrastate motor carriers alike. And the same conclusion was reached in Maurer v. Hamilton, supra, where a state law prohibited any motor carrier from carrying any other vehicle above the cab of the carrier vehicle or over the head of the operator of that vehicle. Cost taken into consideration with other factors might be relevant in some cases to the issue of burden on commerce. ”

“ The District Court fond that 'since it is impossible for a carrier operating in interstate commerce to determine which of its equipment will be used in a particular area, or on a particular day, or days, carriers operating into or through Illinois * * * will be required to equip all their trailers in accordance with the requirements of the Illinois Splash Guard statute.' With two possible exceptions the mudflaps required in those States which have mudguard regulations would not meet the standards required by the Illinois statute. ”

“ Moreover, the contour guard is attached to the trailer by welding and if the trailer is conveying a cargo of explosives (e.g., for the United States Government) it would be exceedingly dangerous to attempt to weld on a contour mudguard without unloading the trailer.
It was also found that the Illinois statute seriously interferes with the 'interline' operations of motor carriers-that is to say, with the interchanging of trailers between an originating carrier and another carrier when the latter serves an area not served by the former. ”

“ Interlining contemplates the physical transfer of the entire trailer; there is no unloading and reloading of the cargo. The interlining process is particularly vital in connection with shipment of perishables, which would spoil if unloaded before reaching their destination, or with the movement of explosives carried under seal. ”

“ These findings on cost and on safety are not the end of our problem. Local regulation of the weight of trucks using the highways upheld in Sproles v. Binford, supra, also involved increased financial burdens for interstate carriers. State control of the width and weight of motor trucks and trailers sustained in South Carolina State Highway Dept. v. Barnwell Bros., supra, involved nice questions of judgment concerning the need of those regulations so far as the issue of safety was concerned. ”