A class of regulations as to which the Court has exhibited marked tolerance although they "incidentally" embrace interstate transportation within their operation are those which purport to be in furtherance of "public safety."[807] The leading case is Smith v. Alabama,[808] in which the Court held it to be within the police power of the State to require locomotive engineers to be examined and licensed, and to enforce this requirement until Congress should decree otherwise in the case of an engineer employed exclusively in interstate transportation. Also upheld as applicable to interstate trains were a statute which forbade the heating of passenger cars by stoves;[809] a municipal ordinance restricting the speed of trains within city limits;[810] the order of a public utility commission requiring the elimination of grade crossings;[811] a statute requiring electric headlights of a specified minimum capacity;[812] a statute requiring three brakemen on freight trains of over twenty-five cars.[813] In the last case the Court admitted that "under the evidence," there was "some room for controversy" as to whether the statute was necessary, but thought it "not so unreasonable as to justify the Court in adjudging it" to be "merely an arbitrary exercise of power" and "not germane" to objects which the State was entitled to accomplish.[814] And in 1943 the Court sustained, though again in somewhat doubtful terms, the order of a State railroad commission requiring a terminal railroad which served both interstate and local commerce to provide caboose cars for its employees.[815] At times, indeed, the Court has made surprising concession to local views that had nothing to do with safety. Hennington v. Georgia,[816] decided in 1896, where was sustained a Georgia statute forbidding freight trains to run on Sunday, is perhaps the supreme example. Whether such an act would pass muster today is doubtful. And earlier statutes reinforcing the legal liability of railroads as common carriers and the carriers of passengers were sustained in the absence of legislation by Congress.[817]
"The principle that, without controlling Congressional action, a State may not regulate interstate commerce so as substantially to affect its flow or deprive it of needed uniformity in its regulation is not to be avoided by 'simply invoking the convenient apologetics of the police power.'" So remarks Chief Justice Stone in his summarizing opinion cited above, in Southern Pacific Co. v. Arizona.[818] Among others he lists the following instances in which State legislation was invalidated on the basis of this rule: "In the Kaw Valley case[819] the Court held that the State was without constitutional power to order a railroad to remove a railroad bridge over which its interstate trains passed, as a means of preventing floods in the district and of improving its drainage, because it was 'not pretended that local welfare needs the removal of the defendants' bridges at the expense of the dominant requirements of commerce with other States, but merely that it would be helped by raising them.' And in Seaboard Air Line R. Co. v. Blackwell,[820] it was held that the interference with interstate rail transportation resulting from a State statute requiring as a safety measure that trains come almost to a stop at grade crossings, outweigh the local interest in safety, when it appealed that compliance increased the scheduled running time more than six hours in a distance of one hundred and twenty-three miles."[821] And "more recently in Kelly v. Washington,"[822] the Chief Justice continued, "we have pointed out that when a State goes beyond safety measures which are permissible because only local in their effect upon interstate commerce, and 'attempts to impose particular standards as to structure, design, equipment and operation [of vessels plying interstate] which in the judgment of its authorities may be desirable but pass beyond what is plainly essential to safety and seaworthiness, the State will encounter the principle that such requirements, if imposed at all, must be through the action of Congress which can establish a uniform rule. Whether the State in a particular matter goes too far must be left to be determined when the precise question arises.'"
STATE REGULATION OF LENGTH OF TRAINS
Applying the test of these precedents, the Chief Justice concluded that Arizona, in making it unlawful to operate within the State a railroad train of more than fourteen passenger or seventy freight cars, had gone "too far"; and in support of this conclusion he recites the following facts: "In Arizona, approximately 93% of the freight traffic and 95% of the passenger traffic is interstate. Because of the Train Limit Law appellant is required to haul over 30% more trains in Arizona than would otherwise have been necessary. The record shows a definite relationship between operating costs and the length of trains, the increase in length resulting in a reduction of operating costs per car. The additional cost of operation of trains complying with the Train Limit Law in Arizona amounts for the two railroads traversing that State to about $1,000,000 a year. The reduction in train lengths also impedes efficient operation. More locomotives and more manpower are required; the necessary conversion and reconversion of train lengths at terminals and the delay caused by breaking up and remaking long trains upon entering and leaving the state in order to comply with the law, delays the traffic and diminishes its volume moved in a given time, especially when traffic is heavy.
"At present the seventy freight car laws are enforced only in Arizona and Oklahoma, with a fourteen car passenger car limit in Arizona. The record here shows that the enforcement of the Arizona statute results in freight trains being broken up and reformed at the California border and in New Mexico, some distance from the Arizona line. Frequently it is not feasible to operate a newly assembled train from the New Mexico yard nearest to Arizona, with the result that the Arizona limitation governs the flow of traffic as far east as El Paso, Texas. For similar reasons the Arizona law often controls the length of passenger trains all the way from Los Angeles to El Paso.
"If one State may regulate train lengths, so may all the others, and they need not prescribe the same maximum limitation. The practical effect of such regulation is to control train operations beyond the boundaries of the State exacting it because of the necessity of breaking up and reassembling long trains at the nearest terminal points before entering and after leaving the regulating State. The serious impediment to the free flow of commerce by the local regulation of train lengths and the practical necessity that such regulation, if any, must be prescribed by a single body having a nation-wide authority are apparent.
"The trial court found that the Arizona law had no reasonable relation to safety, and made train operation more dangerous. Examination of the evidence and the detailed findings makes it clear that this conclusion was rested on facts found which indicate that such increased danger of accident and personal injury as may result from the greater length of trains is more than offset by the increase in the number of accidents resulting from the larger number of trains when train lengths are reduced. In considering the effect of the statute as a safety measure, therefore, the factor of controlling significance for present purposes is not whether there is basis for the conclusion of the Arizona Supreme Court that the increase in length of trains beyond the statutory maximum has an adverse effect upon safety of operation. The decisive question is whether in the circumstances the total effect of the law as a safety measure in reducing accidents and casualties is so slight or problematical as not to outweigh the national interest in keeping interstate commerce free from interferences which seriously impede it and subject it to local regulation which does not have a uniform effect on the interstate train journey which it interrupts."[823]
THE LESSON OF SOUTHERN PACIFIC CO. v. ARIZONA
The lesson to be extracted from Southern Pacific Co. v. Arizona is a threefold one: 1) Where uniformity is judged by the Court to be "essential for the functioning of commerce, a State may not interpose its regulation"; 2) in resolving this question the Court will canvass what it considers to be relevant facts extensively; 3) its task is, however, in the last analysis, one of weighing competing values, in brief, arbitral rather than strictly judicial.