This decision upholds a decision against a facial First Amendment attack ordinances of Los Angeles and several other cities which prohibit mobile billboards—that is, motor vehicles whose principal purpose is displaying advertising.  The ordinances are content neutral, banning all advertising on motor vehicles, other than messages permanently painted on vehicles whose main purpose is transporting persons or goods.  The ordinances were narrowly tailored to avoid traffic problems caused by and unsightliness of mobile billboards.  Advertisers have many other ways in which to get their messages across, so the prohibition of this one means of advertising doesn’t significantly curtail their First Amendment rights.