## Facts

- South Carolina enacted a statute barring use of its highways by motor trucks and semi-trailer trucks that were more than 90 inches wide or more than 20,000 pounds gross weight (including load).
- The restrictions applied equally to in-state and out-of-state carriers, including vehicles engaged in interstate commerce.
- Barnwell Brothers, an interstate trucking company, challenged the statute in federal court, alleging it imposed an unconstitutional burden on interstate commerce and violated the Fourteenth Amendment.
- The district court found the limits would exclude much interstate truck traffic, impede trucking on a connected highway system that included federally improved routes, and increase shipping costs.
- The district court enjoined enforcement of the statute on specified highways as to vehicles engaged in interstate commerce.
- The state highway department appealed to the U.S. Supreme Court.

## Issues

1. Whether, absent federal legislation, a state may impose nondiscriminatory truck width and weight limits on its highways consistent with the Commerce Clause.
2. Whether the width and weight limits are so unreasonable or arbitrary that they violate due process under the Fourteenth Amendment.

## Decision

- The Supreme Court reversed the injunction and upheld the South Carolina statute.
- The Court held that, in the absence of federal legislation, a state may adopt nondiscriminatory regulations limiting vehicle width and weight to conserve highways and promote safety.
- The Court ruled that judicial review is limited to whether the restrictions are reasonably adapted to legitimate state ends, not whether a different regulatory line would be preferable.
- The Court rejected the lower court’s approach of reweighing competing interests and substituting judicial judgment for legislative choice.

## Legal Principles

- In the absence of congressional regulation, states may regulate the use of their highways through nondiscriminatory size and weight limits to protect infrastructure and public safety.
- For evenhanded highway regulations within traditional state authority, Commerce Clause and due process review is confined to whether the measures are reasonably adapted to their stated objectives.
- Courts do not perform the interest-weighing function reserved to Congress and do not select among competing regulatory alternatives when the legislature’s choice has a reasonable relation to legitimate purposes.
- A substantial burden on interstate commerce does not invalidate a state highway regulation if the regulation is nondiscriminatory and reasonably related to safety and road preservation.

## Conclusion

The Court sustained South Carolina’s truck width and weight restrictions, holding that nondiscriminatory highway-safety and road-preservation rules are valid against Commerce Clause and due process challenges when Congress has not legislated and the limits are reasonably related to legitimate state objectives.


S.C. State Highway Dep’t v. Barnwell Bros., Inc., 303 U.S. 177 (1938)