A St. Louis judge has ruled that it’s not unlawful to flash your headlights to signal to other drivers that there are police ahead, the Wall Street Journal’s Law Blog reports. See the full opinion here.

By The Car Spy (2001 Bentley Arnage Red Label) [CC-BY-2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons
The city initially defended its policy—codified as “Limitations on Lamps Other than
Headlamps – Flashing Signals Prohibited Except on Specified Vehicles,” in § 375.100 of its Code of Ordinances—by taking the position that headlight flashing could be interpreted as “illegal interference with a police investigation.” However, in his opinion, U.S. District Judge Henry Autrey pointed to Mo. Rev. Stat. § 575.030, which states that “a warning given in connection with an
effort to bring another into compliance with the law” does NOT constitute a crime of hindering prosecution.
The Ellisville PD said in court that they had already abandoned enforcement of the ordinance in question, which the judge followed up with an official order to that effect.
The Tampa Bay Times has reported similar cases in Florida, including one intended to become a class-action lawsuit that could have required the Sunshine State to pay out more than $150 million in damages to 2,400 recipients of past citations. However, the Orlando Sentinel reported that case was dismissed by a Tallahassee judge after the legislature rewrote the law to end the practice of ticketing high beam flashers. Although this case was not a “win” per se, it did herald a policy change. And that, for some First Amendment advocates, is certainly something to be (ahem) revered.