Horn-Honking and the First Amendment

California law provides,

(a) The driver of a motor vehicle when reasonably necessary to insure safe operation shall give audible warning with his horn.

(b) The horn shall not otherwise be used, except as a theft alarm system.

The Ninth Circuit upheld this law earlier this month, against a challenge brought by a driver who wanted to honk her horn as an expression of support for political process. The court, in Porter v. Martinez (opinion by Judge Michelle Friedland, joined by District Judge Edward Korman, with a dissent by Judge Marsha Berzon), generally reasoned that the law was a content-neutral restriction on expression, and is narrowly tailored to the substantial government interest in traffic safety:

There is nothing novel about Section 27001's traffic-safety justification—in fact, it seems the California legislature had traffic safety in mind when it first enacted a version of Section 27001 in 1913. That early version of the law prohibited honking "for any purpose except as a warning of danger." . The traffic-safety justification for restricting the use of the horn can also be seen in the vehicle codes of at least forty other states, indicating a near-nationwide consensus on the need for such laws. This long history and consensus, coupled with the common-sense inference that the horn's usefulness as a warning tool will decrease the more drivers use it for any other function, support the State's asserted interest in traffic safety.

There's now a petition for en banc rehearing, filed by Porter's lawyer, David Loy of the First Amendment Coalition (a group that I've often represented in Amicus Brief Clinic cases); here's the Introduction:

As drivers commonly do without inci1dent, Porter beeped her horn to support a protest. After being cited for doing so, she brought this First Amendment action. Over Judge Berzon's dissent, the panel majority upheld a ban on expression in a public forum without a single fact showing the expression causes any risk of harm. The majority relied on fact-free conjecture by an "expert" and disregarded facts showing political horn use causes no hazard.

The First Amendment requires the government to prove hard facts before restricting speech. Rule 702 requires a foundation that expert opinion is reliable. By endorsing censorship based on conjecture and admitting speculative opinions from "experience" with no showing of reliability, the majority decision conflicts with the Supreme Court, this Court, and multiple other circuits. It confuses the law, threatens freedom of speech, and opens the door to unreliable opinions whenever a purported "expert" asserts "experience," from product liability actions to personal injury cases to prosecution for numerous offenses. Rehearing en banc is warranted to harmonize this Court's precedent on these vital issues.

An interesting issue; we'll see soon whether the Ninth Circuit agrees to hear the case en banc.