conflicting Congressional legislation. Similarly, in Welch _v._ New
Hampshire[830] a statute of that State establishing maximum hours for
drivers of motor vehicles was held not to be superseded by the Federal
Motor Carrier Act prior to the effective date of regulations by the
Interstate Commerce Commission dealing with the subject. Nor was
pendency before the Interstate Commerce Commission of an application
under the Motor Carrier Act for a license to operate a motor carrier in
interstate commerce found to supersede as to the applicant the authority
of a State to enforce "reasonable regulations" of traffic upon its
highways. "In the absence of the exercise of federal authority," said
the Court, "and in the light of local exigencies, the State is free to
act in order to protect its legitimate interests even though interstate
commerce is directly affected."[831] And for the same reason New York
City was entitled to apply to trucks engaged in the delivery of goods
from New Jersey a traffic regulation forbidding the operation on the
streets of an advertising vehicle.[832] Said Justice Douglas for the
Court: "Many of these trucks are engaged in delivering goods in
interstate commerce from New Jersey to New York. Where traffic control
and the use of highways are involved and where there is no conflicting
federal regulation, great leeway is allowed local authorities, even
though the local regulation materially interferes with interstate
commerce."[833] Also, the Court has consistently sustained State
regulations requiring motor carriers to provide adequate insurance
protection for injuries caused by the negligent operation of their
vehicles.[834]

INVALID STATE ACTS AFFECTING MOTOR CARRIERS

A State law which imposes upon all persons engaged in transporting for
hire by motor vehicle over the public highways of the State the burdens
and duties of common carriers and requires them to furnish bonds to
secure the payment of claims and liabilities resulting from injury to
property carried, may not be validly applied to a private carrier which
is engaged exclusively in hauling from one State to another State the
goods of particular factories under standing contracts with their
owners, the said carrier enjoying neither a special franchise nor using
the eminent domain power.[835] On the other hand, a State statute which
prohibits common carriers for hire from using the highways of the State
between fixed termini or over regular ro