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.
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
Page 303 U. S. 178
the question whether the restrictions imposed are reasonably
adapted to the end sought. P. 303 U. S.
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
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
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.
(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.
(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
(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
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.
Page 303 U. S. 180
MR. JUSTICE STONE delivered the opinion of the Court.
Act No. 259 of the General Assembly of South Carolina, of April
28, 1933, 38 Stat. 340, prohibits use on the state highways of
motor trucks and "semi-trailer motor trucks" whose width exceeds 90
inches, and whose weight including load exceeds 20,000 pounds. For
purposes of the weight limitation § 2 of the statute provides that
a semitrailer motor truck, which is a motor propelled truck with a
trailer whose front end is designed to be attached to and supported
by the truck, shall be considered a single unit. The principal
question for decision is whether these prohibitions impose an
unconstitutional burden upon interstate commerce.
Page 303 U. S. 181
Appellees include the original plaintiffs below, who are
truckers and interstate shippers; the Interstate Commerce
Commission, and certain others who were permitted to intervene as
parties plaintiff. The suit was brought in the district court for
eastern South Carolina against various state officials, to enjoin
them from enforcing §§ 4 and 6 of the Act among others, [Footnote 1
] on the ground that they
have been superseded by the Federal Motor Carrier Act of 1935, c.
498, 49 Stat. 546; that they infringe the due process clause of the
Fourteenth Amendment, and that they impose an unconstitutional
burden on interstate commerce. Certain railroads interested in
restricting the competition of interstate motor carriers were
permitted to intervene as parties defendant.
The district court of three judges, after hearing evidence,
ruled that the challenged provisions of the statute have not been
superseded by the Federal Motor Carrier Act, and adopted as its own
the ruling of the state Supreme Court in State ex rel. Daniel
v. John P. Nutt Co.,
180 S.C.19, 185 S.E. 25, that the
challenged provisions, being an exercise of the state's power to
regulate the use of its highways so as to protect them from injury
and to insure their safe and economical use, do not violate the
Fourteenth Amendment. But it held that the weight and width
prohibitions place an unlawful burden on interstate motor traffic
passing over specified highways of the state, which for the most
part are of concrete or a concrete base surfaced with asphalt. It
accordingly enjoined the enforcement of the weight provision
against interstate motor carriers on the specified highways, and
Page 303 U. S. 182
the width limitation of 90 inches, except in the case of
vehicles exceeding 96 inches in width. It exempted from the
operation of the decree, bridges on those highways "not constructed
with sufficient strength to support the heavy trucks of modern
traffic or too narrow to accommodate such traffic safely," provided
the state highway department should place at each end of the bridge
proper notices warning that the use of the bridge is forbidden by
trucks exceeding the weight or width limits and provided the proper
authorities take the necessary steps to enforce the law against
such use of the bridges. The case comes here on appeal under § 266
of the Judicial Code.
The trial court rested its decision that the statute
unreasonably burdens interstate commerce, upon findings, not
assailed here, that there is a large amount of motor truck traffic
passing interstate in the southeastern part of the United States,
which would normally pass over the highways of South Carolina, but
which will be barred from the state by the challenged restrictions
if enforced, and upon its conclusion that, when viewed in the light
of their effect upon interstate commerce, these restrictions are
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 of the state to accommodate such traffic without
injury to them or danger to their users. It found that interstate
carriage by motor trucks has become a national industry; that from
85% to 90% of the motor trucks used in interstate transportation
are 96 inches wide and of a gross weight, when loaded, of more than
ten tons; that only four other states prescribe a gross load weight
as low as 20,000 pounds, and that the American Association of State
Highway Officials and the National Conference on Street and Highway
Safety in the Department of
Page 303 U. S. 183
Commerce have recommended for adoption weight and width
limitations in which weight is limited to axle loads of 16,000 to
18,000 pounds and width is limited to 96 inches.
It found in detail that compliance with the weight and width
limitations demanded by the South Carolina Act would seriously
impede motor truck traffic passing to and through the state and
increase its cost; that 2,417 miles of state highways, including
most of those affected by the injunction, are of the standard
construction of concrete or concrete base with asphalt surface, 7
1/2 or 8 inches thick at the edges and 6 or 6 1/2 inches thick at
the center; that they are capable of sustaining without injury a
wheel load of 8,000 to 9,000 pounds or an axle load of double those
amounts, depending on whether the wheels are equipped with high
pressure or low pressure pneumatic tires; that all but 100 miles of
the specified highways are from 18 to 20 feet in width; that they
constitute a connected system of highways which have been improved
with the aid of federal money grants, as a part of a national
system of highways, and that they constitute one of the best
highway systems in the southeastern part of the United States.
It also found that the gross weight of vehicles is not a factor
to be considered in the preservation of concrete highways, but that
the appropriate factor to be considered is wheel or axle weight;
the vehicles engaged 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 pounds can be carried
over concrete roads without damage to the surface; that a gross
weight limitation of that amount, especially as applied to
semi-trailer motor trucks, is unreasonable as a means of preserving
the highways; that it has no reasonable relation to safety of the
public using the highways, and that the width limitation of 90
inches is unreasonable
Page 303 U. S. 184
when applied to standard concrete 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
In reaching these conclusions, and at the same time holding that
the weight and width limitations do not infringe the Fourteenth
Amendment, the court proceeded upon the assumption that the
commerce clause imposes upon state regulations to secure the safe
and economical use of highways a standard of reasonableness which
is more exacting when applied to the interstate traffic than that
required by the Fourteenth Amendment as to all traffic; that a
standard of weight and width of motor vehicles which is an
appropriate state regulation when applied to intrastate traffic may
be prohibited because of its effect on interstate commerce,
although the conditions attending the two classes of traffic with
respect to safety and protection of the highways are the same.
South Carolina has built its highways and owns and maintains
them. It has received from the federal government, in aid of its
highway improvements, money grants which have been expended upon
the highways to which the injunction applies. But appellees do not
challenge here the ruling of the district court that Congress has
not undertaken to regulate the weight and size of motor vehicles in
interstate motor traffic, and has left undisturbed whatever
authority in that regard the states have retained under the
While the constitutional grant to Congress of power to regulate
interstate commerce has been held to operate of its own force to
curtail state power in some measure, [Footnote 2
Page 303 U. S. 185
it did not forestall all state action affecting interstate
commerce. Ever since Willson v. Black Bird Creek
2 Pet. 245, and Cooley v.
Board of Port Wardens,
12 How. 299, it has been
recognized that there are matters of local concern, the regulation
of which unavoidably involves some regulation of interstate
commerce but which, because of their local character and their
number and diversity, may never be fully dealt with by Congress.
Notwithstanding the commerce clause, such regulation in the absence
of Congressional action has, for the most part, been left to the
states by the decisions of this Court, subject to the other
applicable constitutional restraints.
The commerce clause, by its own force, prohibits discrimination
against interstate commerce, whatever its form or method, and the
decisions of this Court have recognized that there is scope for its
like operation when state legislation nominally of local concern is
in point of
Page 303 U. S. 186
fact aimed at interstate commerce, or by its necessary operation
is a means of gaining a local benefit by throwing the attendant
burdens on those without the state. Robbins v. Shelby Count
Taxing District, 120 U. S. 489
120 U. S. 498
Caldwell v. North Carolina, 187 U.
, 187 U. S. 626
] It was to end
these practices that the commerce clause was adopted.
See Gibbons v.
9 Wheat. 1, 22 U. S. 187
12 Wheat. 419, 25 U. S.
-439; Cooley v. Board of Port Wardens, supra;
82 U. S.
Wall. 232, 82 U. S. 280
State Tax on Railway Gross
15 Wall. 284, 289 [argument of counsel --
omitted], 82 U. S.
-298; Cook v. Pennsylvania, 97 U. S.
, 97 U. S. 574
Maine v. Grand Trunk R. Co., 142 U.
; Baldwin v. Seelig, 294 U.
, 294 U. S. 522
II Farrand, Records of the Federal Convention, 308; III
478, 574, 548; The Federalist, No. XLII; 1 Curtis,
History of the Constitution, 502; Story on the Constitution, § 259.
The commerce clause has also been thought to set its own limitation
upon state control of interstate rail carriers so as to preclude
the subordination of the efficiency and convenience of interstate
traffic to local service requirements. [Footnote 4
Page 303 U. S. 187
But the present case affords no occasion for saying that the
bare possession of power by Congress to regulate the interstate
traffic forces the states to conform to standards which Congress
might, but has, not adopted, or curtails their power to take
measures to insure the safety and conservation of their highways
which may be applied to like traffic moving intrastate. Few
subjects of state regulation are so peculiarly of local concern as
is the use of state highways. There are few, local regulation of
which is so inseparable from a substantial effect on interstate
commerce. Unlike the railroads, local highways are built, owned and
maintained by the state or its municipal subdivisions. The state
has a primary and immediate concern in their safe and economical
administration. The present regulations, or any others of like
purpose, if they are to accomplish their end, must be applied alike
to interstate and intrastate traffic both moving in large volume
over the highways. The fact that they affect alike shippers in
interstate and intrastate commerce in large number within as well
as without the state is a safeguard against their abuse.
From the beginning, it has been recognized that a state can, if
it sees fit, build and maintain its own highways, canals and
railroads and that, in the absence of Congressional action, their
regulation is peculiarly within its competence, even though
interstate commerce is materially affected. Minnesota Rate
Cases, 230 U. S. 352
230 U. S. 416
Congress not acting, state regulation of intrastate carriers has
been upheld regardless of its effect upon interstate commerce.
With respect to the extent and nature of the local
interests to be protected and the unavoidable effect upon
interstate and intrastate commerce alike, regulations of the use of
the highways are akin to
Page 303 U. S. 188
local regulation of rivers, harbors, piers and docks, quarantine
regulations, and game laws, which, Congress not acting, have been
sustained even though they materially interfere with interstate
commerce. [Footnote 5
Page 303 U. S. 189
The nature of the authority of the state over its own highways
has often been pointed out by this Court. It may not, under the
guise of regulation, discriminate against interstate commerce.
"[i]n the absence of national legislation especially covering
the subject of interstate commerce, the State may rightly prescribe
uniform regulations adapted to promote safety upon its highways and
the conservation of their use, applicable alike to vehicles moving
in interstate commerce and those of its own citizens."
Morris v. Duby, 274 U. S. 135
274 U. S. 143
This formulation has been repeatedly affirmed, Clark v.
Poor, 274 U. S. 554
274 U. S. 557
Sprout v. South Bend, 277 U. S. 163
277 U. S. 169
Sproles v. Binford, 286 U. S. 374
286 U. S. 389
390; cf. Morf v. Bingaman, 298 U.
, and never disapproved. This Court has often
sustained the exercise of that power although it has burdened or
impeded interstate commerce. It has upheld weight limitations lower
than those presently imposed, applied alike to motor traffic moving
interstate and intrastate. Morris v. Duby, supra; Sproles v.
Restrictions favoring passenger traffic over
the carriage of interstate merchandise by truck have been similarly
sustained, Sproles v. Binford, supra; Bradley v. Public
Utilities Comm'n, 289 U. S. 92
has the exaction of a reasonable fee for the use of the highways.
Hendrick v. Maryland, 235 U. S. 610
Kane v. New Jersey, 242 U. S. 160
Interstate Busses Corp. v. Blodgett, 276 U.
; Morf v. Bingaman, supra; cf. Ingels v.
Morf, 300 U. S. 290
In each of these cases, regulation involves a burden on
interstate commerce. But so long as the state action does not
discriminate, the burden is one which the Constitution permits
because it is an inseparable incident of the exercise of a
legislative authority which, under the Constitution, has been left
to the states.
Congress, in the exercise of its plenary power to regulate
interstate commerce, may determine whether the
Page 303 U. S. 190
burdens imposed on it by state regulation, otherwise
permissible, are too great, and may, by legislation designed to
secure uniformity or in other respects to protect the national
interest in the commerce, curtail to some extent the state's
regulatory power. But that is a legislative, not a judicial,
function, to be performed in the light of the Congressional
judgment of what is appropriate regulation of interstate commerce,
and the extent to which, in that field, state power and local
interests should be required to yield to the national authority and
interest. In the absence of such legislation, the judicial
function, under the commerce clause as well as the Fourteenth
Amendment, stops with the inquiry whether the state legislature, in
adopting regulations such as the present, has acted within its
province, and whether the means of regulation chosen are reasonably
adapted to the end sought. Sproles v. Binford, supra;
Stephenson v. Binford, 287 U. S. 251
287 U. S.
Here, the first inquiry has already been resolved by our
decisions that a state may impose nondiscriminatory restrictions
with respect to the character of motor vehicles moving in
interstate commerce as a safety measure and as a means of securing
the economical use of its highways. In resolving the second, courts
do not sit as legislatures, either state or national. They 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. And in reviewing a state highway regulation
where Congress has not acted, a court is not 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. Transportation Co. v.
Parkersburg, 107 U. S. 691
107 U. S. 695
When the action of a legislature is
Page 303 U. S. 191
within the scope of its power, fairly debatable questions as to
its reasonableness, wisdom and propriety are not for the
determination of courts, but for the legislative body, on which
rests the duty and responsibility of decision. Jacobson v.
Massachusetts, 197 U. S. 11
197 U. S. 30
Laurel Hill Cemetery v. San Francisco, 216 U.
, 216 U. S. 365
Price v. Illinois, 238 U. S. 446
238 U. S. 451
Hadacheck v. Sebastian, 239 U. S. 394
239 U. S.
-414; Thomas Cusack Co. v. Chicago,
242 U. S. 526
242 U. S. 530
Euclid v. Ambler Realty Co., 272 U.
, 272 U. S. 388
Zahn v. Board of Public Works, 274 U.
, 274 U. S. 328
Standard Oil Co. v. Marysville, 279 U.
, 279 U. S. 584
This is equally the case when the legislative power is one which
may legitimately place an incidental burden on interstate commerce.
It is not any the less a legislative power committed to the states
because it affects interstate commerce, and courts are not any the
more entitled, because interstate commerce is affected, to
substitute their own for the legislative judgment. Morris v.
Duby, supra, 274 U. S. 143
Sproles v. Binford, supra, 286 U. S. 389
286 U. S. 390
Minnesota Rate Cases, supra, 230 U. S. 399
230 U. S. 400
Smith v. St. Louis & S.W. R. Co., 181 U.
, 181 U. S. 257
Reid v. Colorado, 187 U. S. 137
187 U. S. 152
New York ex rel. Silz v. Hesterberg, 211 U. S.
, 211 U. S. 42
211 U. S.
Since the adoption of one weight or width regulation, rather
than another, is a legislative, not a judicial, choice, its
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. Cf. Worcester County Trust Co. v.
Riley, 302 U. S. 292
302 U. S. 299
Being a legislative judgment it is presumed to be supported by
facts known to the legislature unless facts judicially known or
proved preclude that possibility. Hence, in reviewing the present
determination, we examine the record not to see whether the
findings of the court below are supported by evidence, but to
ascertain upon the whole
Page 303 U. S. 192
record whether it is possible to say that the legislative choice
is without rational basis. Standard Oil Co. v. Marysville,
supra; Borden's Farm Products Co. v. Ten Eyck, 297 U.
, 297 U. S. 263
s.c. 11 F. Supp.
, 600. Not only does the record fail to exclude that
possibility, but it shows affirmatively that there is adequate
support for the legislative judgment.
At the outset, it should be noted that underlying much of the
controversy is the relative merit of a gross weight limitation as
against an axle or wheel weight limitation. While there is evidence
that weight stresses on concrete roads are determined by wheel,
rather than gross load, weights, other elements enter into choice
of the type of weight limitation. There is testimony to show that
the axle or wheel weight limitation is the more easily enforced
through resort to weighing devices adapted to ascertaining readily
the axle or wheel weight. But it appears that, in practice, the
weight of truck loads is not evenly distributed over axles and
wheels; that commonly the larger part of the load -- sometimes as
much as 70% to 80% -- rests on the rear axle, and that it is much
easier for those who load trucks to make certain that they have
complied with a gross load weight limitation than with an axle or
wheel weight limitation. While the report of the National
Conference on State and Highway Safety, on which the court below
relied, suggested a wheel weight limitation of 8,000 or 9,000
pounds, it also suggested that a gross weight limitation might be
adopted, and should be subject to the recommended wheel limitation.
But the conference declined to fix the amount of gross weight
In view of the varying conditions of traffic, and lack of
uniformity in highway construction in the several States, no
uniform gross weight limitations are here recommended for general
adoption throughout the country.
The choice of a weight limitation based on convenience of
application, and consequent lack of
Page 303 U. S. 193
need for rigid supervisory enforcement, is for the legislature,
and we cannot say that its preference for the one over the other is
in any sense arbitrary or unreasonable. The choice is not to be
condemned because the legislature prefers a workable standard, less
likely to be violated than another under which the violations will
probably be increased but more easily detected. It is for the
legislature to say whether the one test or the other will, in
practical operation, better protect the highways from the risk of
If gross load weight is adopted as the test, it is obvious that
the permissible load must be somewhat lighter than if the axle or
wheel weight test were applied. With the latter, the gross weight
of a loaded motor truck can never exceed twice the axle and four
times the wheel limit. But the fact that the rear axle may and
often does support as much as 70% or 80% of the gross load, with
wheel weight in like proportion, requires that a gross load limit
be fixed at considerably less than four times the permissible wheel
There was testimony before the court to support its conclusion
that the highways in question are capable of sustaining without
injury a wheel load of 8,000 or 9,000 pounds, the difference
depending upon the character of the tire in use, as against a wheel
load of as much as 8,000 pounds, which would be possible under the
statutory load limit of 20,000 pounds as applied to motor trucks,
and approximates the axle limit in addition to the gross load limit
recommended by the National Conference on Street and Highway
Safety. Much of this testimony appears to have been based on
theoretical strength of concrete highways laid under ideal
conditions, and none of it was based on an actual study of the
highways of South Carolina or of the subgrade and other road
building conditions which prevail there and which have a material
bearing on the strength and durability of such highways. There
Page 303 U. S. 194
uncontradicted testimony that approximately 60% of the South
Carolina standard paved highways in question were built without a
longitudinal center joint which has since become standard practice,
the portion of the concrete surface adjacent to the joint being
strengthened by reinforcement or by increasing its thickness, and
that, owing to the distribution of the stresses on concrete roads
when in use, those without a center joint have a tendency to
develop irregular longitudinal cracks. As the concrete in the
center of such roads is thinner than that at the edges, the result
is that the highway is split into two irregular segments, each with
a weak inner edge which, according to the expert testimony, is not
capable of supporting indefinitely wheel loads in excess of 4,200
There is little in the record to mark any controlling
distinction between the application of the gross load weight
limitation to the motor truck and to the semitrailer motor truck.
There is testimony which is applicable to both types of vehicle,
that, in case of accident, the danger from the momentum of a
colliding vehicle increases with gross load weight. The record is
without convincing evidence of the actual distribution, in
practice, of the gross load weight over the wheels and axles of the
permissible types of semi-trailer motor trucks, but this does not
enable us to say that the legislature was without substantial
ground for concluding that the relative advantages of a gross load
over a wheel weight limitation are substantially the same for the
two types, or that it could not have concluded that they were so
nearly alike for regulatory purposes as to justify the adoption of
a single standard for both, as a matter of practical convenience.
Even if the legislature were to accept appellees' assumption that
net load weights are, in practice, evenly distributed over the
wheels supporting the load of a permissible semi-trailer so that
with the statutory gross
Page 303 U. S. 195
load limit the load on the rear axle would be about 8,000
pounds, it might, as we have seen, also conclude that the danger
point would then have been reached in the case of some 1,200 miles
of concrete state roads constructed without a center joint.
These considerations, with the presumption of constitutionality,
afford adequate support for the weight limitation without reference
to other items of the testimony tending to support it. Furthermore,
South Carolina's own experience is not to be ignored. Before
adoption of the limitation South Carolina had had experience with
higher weight limits. In 1924, it had adopted a combined gross
weight limit of 20,000 pounds for vehicles of four wheels or less,
and an axle weight limit of 15,000 pounds. In 1930, it had adopted
a combined gross weight limit of 12 1/2 tons with a five-ton axle
weight limit for vehicles having more than two axles. Act No. 721,
33 Stat. 1182; Act No. 685, 36 Stat. 1192, 1193. In 1931, it
appointed a commission to investigate motor transportation in the
state, to recommend legislation, and to report in 1932. The present
weight limitation was recommended by the commission after a full
consideration of relevant data, including a report by the state
engineer who had constructed the concrete highways of the state and
who advised a somewhat lower limitation as necessary for their
preservation. The fact that many states have adopted a different
standard is not persuasive. The conditions under which highways
must be built in the several states, their construction and the
demands made upon them, are not uniform. The roadbuilding art, as
the record shows, is far from having attained a scientific
certainty and precision, and scientific precision is not the
criterion for the exercise of the constitutional regulatory power
of the states. Sproles v. Binford, supra, 286 U. S. 388
The legislature, being free to exercise its own judgment, is not
bound by that of other legislatures. It would hardly be
Page 303 U. S. 196
that, if all the states had adopted a single standard, none, in
the light of its own experience and in the exercise of its judgment
upon all the complex elements which enter into the problem, could
Only a word need be said as to the width limitation. While a
large part of the highways in question are from 18 to 20 feet in
width, approximately 100 miles are only 16 feet wide. On all, the
use of a 96-inch truck leaves but a narrow margin for passing. On
the road 16 feet wide it leaves none. The 90-inch limitation has
been in force in South Carolina since 1920, and the concrete
highways which it has built appear to be adapted to vehicles of
that width. The record shows without contradiction that the use of
heavy loaded trucks on the highways tends to force other traffic
off the concrete surface onto the shoulders of the road adjoining
its edges, and to increase repair costs materially. It appears also
that, as the width of trucks is increased, it obstructs the view of
the highway, causing much inconvenience and increased hazard in its
use. It plainly cannot be said that the width of trucks used on the
highways in South Carolina is unrelated to their safety and cost of
maintenance, or that a 90-inch width limitation, adopted to
safeguard the highways of the State, is not within the range of the
permissible legislative choice.
The regulatory measures taken by South Carolina are within its
legislative power. They do not infringe the Fourteenth Amendment,
and the resulting burden on interstate commerce is not
MR. JUSTICE CARDOZO and MR. JUSTICE REED took no part in the
consideration or decision of this case.
"§ 4. Weight. -- No person shall operate on any highway any
motor truck or semi-trailer truck [sic
] whose gross
weight, including load, shall exceed 20,000 pounds."
"§ 6. Width. -- No person shall operate on any highway any motor
truck or semi-trailer motor truck whose total outside width,
including any part of body or load, shall exceed 90 inches."
State regulations affecting interstate commerce, whose purpose
or effect is to gain for those within the state an advantage at the
expense of those without, or to burden those out of the state
without any corresponding advantage to those within, have been
thought to impinge upon the constitutional prohibition even though
Congress has not acted. Hall v. DeCuir, 95 U. S.
, 95 U. S.
-498; Wabash, St. L. & P. R. Co. v.
Illinois, 118 U. S. 557
118 U. S.
-578; Bowman v. Chicago & N.W. R. Co.,
125 U. S. 465
125 U. S. 498
Western Union Telegraph Co. v. James, 162 U.
, 162 U. S. 659
with which compare Western Union Telegraph Co. v.
Pendleton, 122 U. S. 347
122 U. S. 358
Foster-Fountain Packing Co. v. Haydel, 278 U. S.
, with which compare Geer v. Connecticut,
161 U. S. 519
and New York ex rel. Silz v. Hesterberg, 211 U. S.
; Baldwin v. Seelig, 294 U.
, 294 U. S. 524
see Western Union Telegraph Co. v. Kansas, 216 U. S.
, 216 U. S. 27
Underlying the stated rule has been the thought, often expressed
in judicial opinion, that, when the regulation is of such a
character that its burden falls principally upon those without the
state, legislative action is not likely to be subjected to those
political restraints which are normally exerted on legislation
where it affects adversely some interests within the state.
See Cooley v. Board of Port
12 How. 299, 315; Gilman v.
3 Wall. 713, 70 U. S. 731
Escanaba Co. v. Chicago, 107 U. S. 678
107 U. S. 683
Lake Shore & M. S. R. Co. v. Ohio ex rel. Lawrence,
173 U. S. 285
173 U. S. 294
cf. Pound v. Turck, 95 U. S. 459
95 U. S. 464
Gloucester Ferry Co. v. Pennsylvania, 114 U.
, 114 U. S. 205
Robbins v. Shelby County Taxing District, 120 U.
, 120 U. S.
See Illinois Central R. Co. v. Illinois, 163 U.
; Cleveland, C.C. & St.L. R. Co. v.
Illinois, 177 U. S. 514
Mississippi Railroad Comm'n v. Illinois Central R. Co.,
203 U. S. 335
Atlantic Coast Line R. Co. v. Wharton, 207 U.
; Herndon v. Chicago, R.I. & P. R.
Co., 218 U. S. 135
Chicago, B. & Q. R. Co. v. Railroad Commission,
237 U. S. 220
St. Louis & San Francisco R. Co. v. Public Service
Comm'n, 254 U. S. 535
Cf. Gladson v. Minnesota, 166 U.
; Lake Shore & M. S. R. Co. v. Ohio ex
rel.Lawrence, 173 U. S. 285
Gulf, C. & S.F. R. Co. v. Texas, 246 U. S.
, where statutes requiring local service no greater
than necessary for fair accommodation of local needs were held
constitutional. Although the states have usually been allowed to
impose burdens on interstate railroads in the interest of local
safety, Smith v. Alabama, 124 U.
; Nashville, C. & St.L. R. Co. v.
Alabama, 128 U. S. 96
New York, N.H. & H. R. Co. v. New York, 165 U.
; Chicago, R.I. & P. R. Co. v.
Arkansas, 219 U. S. 453
St. Louis, I. M. & S. R. Co. v. Arkansas, 240 U.
; cf. Hennington v. Georgia, 163 U.
, an unnecessarily harsh restriction, even though
it is in the interest of safety, has been held to be
unconstitutional. Seaboard Air Line R. v. Blackwell,
244 U. S. 310
Among the state regulations materially affecting interstate
commerce which this Court has upheld, Congress not acting, are
those which sanction obstructions in navigable rivers,
Willson v. Black-Bird Creek
2 Pet. 245; Ex parte
13 Wall. 236; Pound v. Turck,
95 U. S. 459
Wilson v. McNamee, 102 U. S. 572
Huse v. Clover, 119 U. S. 543
cf. Sands v. Manistee River Improvement Co., 123 U.
; approve the erection of bridges over navigable
streams, Gilman v.
3 Wall. 713; Escanaba Co. v.
Chicago, 107 U. S. 678
Cardwell v. American River Bridge Co., 113 U.
; Willamette Iron Bridge Co. v. Hatch,
125 U. S. 1
Lake Shore & M. S. R. Co. v. Ohio, 165 U.
; require payment of fees as an incident to use of
harbors, Cooley v. Board of Port
12 How. 299; Steamship
Co. v. Joliffe,
2 Wall. 450; Anderson v.
Pacific Coast S.S. Co., 225 U. S. 187
Clyde Mallory Lines v. Alabama ex rel. State Docks Comm'n,
296 U. S. 261
cf. Mobile County v. Kimball, 102 U.
; control the location of docks, Cummings v.
Chicago, 188 U. S. 410
impose wharfage charges, Packet Co. v. Keokuk,
95 U. S. 80
Packet Co. v. Catlettsburg, 105 U.
; Transportation Co. v. Parkersburg,
107 U. S. 691
Ouachita Packet Co. v. Aiken, 121 U.
; establish inspection and quarantine laws,
Turner v. Maryland, 107 U. S. 38
Morgan's S.S. Co. v. Louisiana Board of Health,
118 U. S. 455
Patapsco Guano Co. v. North Carolina Board of Agriculture,
171 U. S. 345
Rasmussen v. Idaho, 181 U. S. 198
Smith v. St. Louis & S.W. R. Co., 181 U.
; Reid v. Colorado, 187 U.
; New Mexico ex rel. McLean Co. v. Denver
& R.G. R. Co., 203 U. S. 38
Asbell v. Kansas, 209 U. S. 251
Red "C" Oil Mfg. Co. v. Board of Agriculture, 222 U.
; Savage v. Jones, 225 U.
; Pure Oil Co. v. Minnesota, 248 U.
; Mintz v. Baldwin, 289 U.
; cf. Railroad Co. v. Husen, 95 U. S.
; Minnesota v. Barber, 136 U.
; Brimmer v. Rebman, 138 U. S.
, and regulate the taking or exportation of domestic
game, Geer v. Connecticut, 161 U.
; New York ex rel. Silz v. Hesterberg,
211 U. S. 31
cf. Foster-Fountain Packing Co. v. Haydel, 278 U. S.
, 278 U. S. 13
holding invalid a local regulation ostensibly designed to conserve
a natural resource but whose purpose and effect were to benefit
Louisiana enterprise at the expense of businesses outside the