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By David L. Hudson Jr., published on February 5, 2024

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Photo courtesy iStock: Nopphon Pattanasri

Is horn honking a form of free speech protected by the First Amendment? The U.S. Supreme Court could answer this question if it grants review in Porter v. Martinez.

The case began in 2017 when Susan Porter drove her vehicle past a group of protesters outside a government building in San Diego County. Porter honked her horn in support of the protesters. The police then gave her a citation for violating a California law that prohibits honking horns except to avoid or prevent an accident.  

Porter filed a First Amendment-based challenge to the law, contending that honking one’s horn can be a form of free expression protected by the First Amendment. Both a federal district court and the 9th U.S. Circuit Court of Appeals ruled against her. 

However, Porter has now filed a petition for writ of certiorari to the U.S. Supreme Court. Her cert. petition contends that horn honking is a longstanding form of expression and protest.

“The car horn is the sound of democracy in action,” the petition reads.  

The petition adds that both President Joe Biden and former President Donald Trump have advocated the use of horn honking during political campaign rallies.  

Courts have reached different results in cases involving horn honking and First Amendment claims. Some courts have upheld citations for drivers who honk horns in a non-traffic-warning way. They contend that the ban on excessive horn honking helps traffic safety and prevents excessive noise pollution. 

However, other courts have recognized that the honking of a horn can convey a variety of messages. Many different types of protesters have utilized horn honking as a way to advocate causes or express displeasure at government policies.  

Porter’s cert. petition ends with the following appeal to the Supreme Court:

“Allowing the Ninth Circuit’s decision to stand would cast a pall over ordinary citizens who will be deterred from honking their horns in support of political causes close to their heart—a long-standing practice—for fear of criminal prosecution.”

David L. Hudson Jr. teaches First Amendment law and constitutional law classes at Belmont University College of Law. He is the author, co-author, or co-editor of more than 50 books, including The Constitution Explained: A Guide for Every American (Visible Ink Press, 2022) and The First Amendment: Freedom of Speech (Thomson Reuters, 2012).  

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