ACLU suit targets law that bars horn honking at protests – By When an Oceanside woman beeped her car horn in support of a political protest last year, the 63-year-old quickly found herself pulled over and ticketed. The problem? According to the state vehicle code, horns are to be honked only for safety reasons or as part of a car alarm. Now, the American Civil Liberties Union of San Diego and Imperial Counties is asking a federal judge to find that state law unconstitutional, arguing in a newly filed lawsuit that preventing such honking chills free speech.