D passed an ordinance imposing substantial prohibitions on the erection of outdoor advertising displays within the city. The purpose was 'to eliminate hazards to pedestrians and motorists brought about by distracting sign displays' and 'to preserve and improve the appearance of the City.' The ordinance provided two kinds of exceptions to the general prohibition: onsite signs and signs falling within 12 specified categories. Onsite commercial advertising is permitted, but other commercial advertising and noncommercial communications using fixed-structure signs are everywhere forbidden unless permitted by one of the specified exceptions. Metromedia (Ps) were companies that were engaged in the outdoor advertising business in San Diego at the time the ordinance was passed. Each owns a substantial number of outdoor advertising displays within D. Besides commercial messages, their billboards have also been used to convey a broad range of noncommercial political and social messages. Ps sued D alleging that the ordinance was a violation of the First Amendment and unconstitutional on its face. After extensive discovery, it was stipulated that the ordinance would destroy and eliminate the business of outdoor advertising in D and that many businesses resorted to outdoor advertising because other forms of advertisement were insufficient. The court held the ordinance unconstitutional, the appeals court agreed, but the California Supreme Court reversed in that the ordinance was constitutionally permissible. It held that the two purposes of the ordinance were within the city's legitimate interests and that the ordinance was 'a proper application of municipal authority over zoning and land use for the purpose of promoting the public safety and welfare.' The Supreme Court granted certiorari.