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Southern Pacific Co. v. Arizona

Supreme Court of the United States · 1945 · Constitutional Law

Constitutional LawCommerce ClauseDormant Commerce ClauseState Police PowerRailroad RegulationCommerce Clausedormant commerce clausebalancing

Facts

Arizona's Train Limit Law made it unlawful to operate within the state passenger trains of more than fourteen cars or freight trains of more than seventy cars, and imposed a monetary penalty for each violation. Southern Pacific admitted operating interstate trains longer than those limits and argued that the law conflicted with federal law and violated the Commerce Clause. The findings showed that long trains were standard practice nationally, that Arizona traffic was overwhelmingly interstate, and that compliance with the law required the railroad to run over 30% more trains in Arizona, increasing costs and causing delay from breaking up and reassembling trains at terminals near the state borders. The findings also showed that any safety benefit from shorter trains was at most slight and uncertain because the increase in the number of trains increased other accidents, often more serious than slack-action accidents.

Issue

Whether Congress had already displaced state authority to regulate interstate train lengths and, if not, whether Arizona's train-limit law violated the Commerce Clause by placing an impermissible burden on interstate commerce.

Rule

In the absence of controlling congressional action, a state may regulate matters of local concern affecting interstate commerce only so long as the regulation does not materially restrict the free flow of interstate commerce or interfere with matters for which uniform national regulation is of predominant concern. Where a state safety measure seriously burdens interstate commerce and the asserted safety benefits are slight or problematical, the Commerce Clause forbids the state regulation.

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One of 10 multiple-choice questions for this case. Pick an answer to see why.

New Mexico enacts a statute limiting all freight trains within the state to 60 cars. Sierra Basin Rail, whose traffic through New Mexico is 94% interstate, shows that compliance requires trains to be split at yards near Albuquerque and El Paso, adds crews and locomotives, and increases annual operating costs substantially; the state offers studies suggesting only a modest reduction in one type of rail-yard injury, while total accident effects remain disputed.

If Congress has not enacted controlling legislation on train length, how should a court most likely rule on Sierra Basin Rail's Commerce Clause challenge?

Explanation. The majority held that, absent controlling congressional action, a state safety measure affecting interstate rail operations is unconstitutional when it materially impedes interstate commerce, destroys needed operational uniformity, and yields only slight or dubious safety benefits. Train length is a subject for which national uniformity is practically indispensable because differing state limits force breakups and reassembly and allow one state's rule to govern operations beyond its borders.