A quick flash of bight headlights is a driver-to-driver warning only some know about and many police officers don't like, but a federal trial judge has ruled it is protected free speech. In Minnesota, the rules aren't so clear.
Many languages evolve and change over time, and it seems that flashing headlights to another driver on the road is hardly a universal symbol for anything these days. Yet, in many areas, a couple of flashes can signal there is a cop waiting up the road with a speed gun -- and a federal trial judge in Missouri says those speed trap warnings are constitutionally protected free speech.
"I think, at this point, the case may be unsettled," CLA Law Professor Eugene Volokh -- the go-to expert on the topic, said.
According to Volokh, intent is what counts.
"What was he saying? Watch out for police or watch out and drive safely?" he questions.
In Minnesota, there is no specific law preventing drivers from warning other motorists about speed traps, but that doesn't mean anyone who tries it out won't get a ticket. State law says headlights must be on continuously a half hour before sunset and after sunrise, but high-beams may not be used within 1,000 feet of an oncoming vehicle. That may allow officers to initiate a stop.
"Officers can certainly stop someone," John Elder, with the Minneapolis Police Department, confirmed. "It's up to the officer whether they want to issue a ticket, but they can certainly stop for it."
NOTE: Subsequent to our broadcast, Fox 9 News learned of a legal decision in Minnesota -- Sarber v. Commissioner of Public Safety -- in which an appellate court found that briefly flashing high beams at an oncoming car is not a traffic violation.
These days, warnings tend to be more high-tech anyway. Waze is a traffic app that encourages drivers to report police activity -- including whether the cops are visible or hidden. Of course, police can also pull over a driver they suspect of texting behind the wheel too.
The Minnesota State Patrol said their main concern with flashing headlights to communicate with other drivers isn't keeping speed traps a secret. Rather, it's about avoiding creating additional distractions on the roads.
"It's really a traffic safety issue for us -- not so much for warning other drivers," Lt. Eric Roeske said.