US SUPREME COURT DECISIONS

1. In the absence of national legislation covering the subject in its relation to interstate commerce, a State, in order to conserve its highways and promote safety thereon, may adopt regulations limiting the weight and width of the vehicles that use them, applicable without discrimination to those moving in interstate commerce and to those moving only within the State. P. 303 U. S. 184.

2. Such regulations being, in general, within the competency of the State, judicial inquiry into their validity, under the commerce clause as well as under the Fourteenth Amendment, is limited to chanrobles.com-red

Page 303 U. S. 178

the question whether the restrictions imposed are reasonably adapted to the end sought. P. 303 U. S. 190.

In resolving this question, the court cannot act as Congress does when, after weighing all the conflicting interests, state and national, it determines when and how much the state regulatory power shall yield to the larger interests of a national commerce; nor is it called upon, as are state legislatures, to determine what, in its judgment, is the most suitable restriction to be applied of those that are possible, or to choose that one which in its opinion is best adapted to all the diverse interests affected.

3. A South Carolina statute prohibits use on the state highways of motor trucks and "semi-trailer" motor trucks wider than 90 inches or heavier, including load, than 20,000 lbs. A federal court enjoined its enforcement on specified highways as to vehicles engaged in interstate commerce. It found that much of the interstate motor-truck traffic normally passing over these highways would be barred from the State if the restrictions were enforced, and concluded that, in the light of their effect upon interstate commerce, the restrictions were unreasonable. To reach this conclusion, the court weighed conflicting evidence and made its own determinations as to the weight and width of motor trucks commonly used in interstate traffic and the capacity of the specified highways to accommodate such traffic. without injury to them or danger to their users. It found, among other things, that interstate carriage by motor truck has become a national industry; that a very large proportion of the trucks used in interstate transportation are 96 inches wide and of gross weight, when loaded, of more than 10 tons; that the specified highways constitute a connected system, improved with the aid of federal money grants, as a part of a national system; that not gross weight, but wheel or axle weight, is the factor to be considered in the preservation of concrete highways; that the vehicles used in interstate commerce are so designed and the pressure of their weight is so distributed by their wheels and axles that gross loads of more than 20,000 lbs. can be carried over concrete roads without damage to the surface; that the highways in question could sustain without injury a wheel load of from 8,000 to 9,000 lbs. or an axle load of double those weights; that the weight limitation of the statute, especially as applied to semi-trailer motor trucks, is unreasonable as a means of preserving the highways and has no reasonable relation to safety of the public using them, and that the width limitation of 90 inches is unreasonable when applied to standard concrete chanrobles.com-red

Page 303 U. S. 179

highways of the State, in view of the fact that all other States permit a width of 96 inches, which is the standard width of trucks engaged in interstate commerce.

Held:

(1) That since the adoption of one weight or width regulation, rather than another is a legislative not a judicial choice, constitutionality is not to be determined by weighing in the judicial scales the merits of the legislative choice and rejecting it if the weight of evidence presented in court appears to favor a different standard. P. 303 U. S. 191.

(2) The legislative judgment is presumed to be supported by facts known to the legislature unless facts judicially known or proved preclude that possibility. Id.

(3) In reviewing the present determination, this Court must examine the record, not to see whether the findings of the court below are supported by evidence, but to ascertain whether it is possible to say that the legislative choice is without rational basis. Id.

(4) Not only does the record fail to exclude that possibility, but it shows affirmatively that there is adequate support for the legislative judgment. Pp. 303 U. S. 192 et seq.

17 F..2d 803, reversed.

APPEAL from a final decree of a district court of three judges which enjoined the South Carolina State Highway Department, the State Public Service Commission and numerous state officers, from enforcing, as against the plaintiffs while engaged in interstate commerce on certain specified highways, a statute limiting the weight and width of motor trucks and "semi-trailer" trucks. There was a provision in the decree that the injunction should not extend to bridges not strong enough to support heavy trucks or too narrow to accommodate such traffic safely, with a proviso that the State Highway Department should post certain warning notices at such bridges, and should enforce the law against their use by such trucks. The Interstate Commerce Commission and two private corporations were permitted to intervene as plaintiffs, and two railroad companies and the receiver of another were permitted to intervene as defendants. chanrobles.com-red

Page 303 U. S. 180