A federal judge in St. Louis ruled Monday that a driver flashing their lights to warn other drivers of an impending speed trap is protected free speech.

On November 22, 2012 Michael Elli received a ticket for flashing his lights to warn fellow drivers of a speed trap, according to Fox 2. The American Civil Liberties Union helped Elli fight the $1,000 ticket all the way to federal court.

Judge Henry Autrey of St. Louis ruled a driver has the right to flash their lights under the First Amendment. Autrey issued an injunction to stop Ellisville Police from enforcing the policy.

"If you're at the gas station on the corner and someone says 'Hey be careful over there, there's a speed trap,' that's protected speech. You can't be ticketed for that. This is no different," Tony Rothert, an attorney for the American Civil Liberties Union, told Fox 2.

A lawyer for the police in Ellisville said the department isn't affected by the ruling, as this kind of ticket has only been issued five or so times in the last decade. Across the country, however, the ruling will be considered the benchmark for such cases.