Fourteenth Amendment, Section 1:
All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside. No State shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States; nor shall any State deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws.
Regulations designed to promote public safety are also well within a state’s authority. For instance, various measures designed to reduce fire hazards have been upheld. These include municipal ordinances that prohibit the storage of gasoline within 300 feet of any dwelling, 1 require that all gas storage tanks with a capacity of more than ten gallons be buried at least three feet under ground, 2 or prohibit washing and ironing in public laundries and wash houses within defined territorial limits from 10 p.m. to 6 a.m. 3 A city’s demolition and removal of wooden buildings erected in violation of regulations was also consistent with the Fourteenth Amendment. 4 Construction of property in full compliance with existing laws, however, does not confer upon the owner an immunity against exercise of the police power. Thus, a 1944 amendment to a Multiple Dwelling Law, requiring installation of automatic sprinklers in lodging houses of non-fireproof construction, can be applied to a lodging house constructed in 1940, even though compliance entails an expenditure of $7,500 on a property worth only $25,000. 5
States exercise extensive regulation over transportation safety. Although state highways are used primarily for private purposes, they are public property, and the use of a highway for financial gain may be prohibited by the legislature or conditioned as it sees fit. 6 Consequently, a state may reasonably provide that intrastate carriers who have furnished adequate, responsible, and continuous service over a given route from a specified date in the past shall be entitled to licenses as a matter of right, but that issuance to those whose service began later shall depend upon public convenience and necessity. 7 A state may require private contract carriers for hire to obtain a certificate of convenience and necessity, and decline to grant one if the service of common carriers is impaired thereby. A state may also fix minimum rates applicable to such private carriers, which are not less than those prescribed for common carriers, as a valid as a means of conserving highways. 8 In the absence of legislation by Congress, a state may, to protect public safety, deny an interstate motor carrier the use of an already congested highway. 9
In exercising its authority over its highways, a state is not limited to the raising of revenue for maintenance and reconstruction or to regulating the manner in which vehicles shall be operated, but may also prevent the wear and hazards due to excessive size of vehicles and weight of load. 10 No less constitutional is a municipal traffic regulation that forbids the operation in the streets of any advertising vehicle, excepting vehicles displaying business notices or advertisements of the products of the owner and not used mainly for advertising; and such regulation may be validly enforced to prevent an express company from selling advertising space on the outside of its trucks. 11 A state may also provide that a driver who fails to pay a judgment for negligent operation shall have his license and registration suspended for three years, unless, in the meantime, the judgment is satisfied or discharged. 12 Compulsory automobile insurance is so plainly valid as to present no federal constitutional question. 13