The city of San Diego, CA, enacted a city zoning ordinance that prohibited outdoor advertising display signs, including billboards. On-site at a business location were exempted from this rule. The city based the restriction on traffic safety and aesthetics. Metromedia, INC, a company that is in the business of leasing commercial billboards to advertisers, sued the city of San Diego, alleging that the zoning ordinance is unconstitutional. Is it?