JOPLIN, Mo. — Flashing headlights can actually mean a few different things, depending on the context.

Fortunately, it only takes a second to check the two most common things the other driver is trying to communicate: Your own headlights, and the potential dangers ahead of you on the road (and despite what you may have heard, it’s not a gang initiation ritual.)

But a quick flash of the headlights typically means the presence of law enforcement ahead, with radar, trying to catch speeders.

So the question becomes, is it legal to flash your headlights for this reason?

According to Iowa State Patrol Sergeant Alex Dinkla, it is, indeed, illegal to flash headlights in Iowa. While the act of flashing headlights to warn of speed traps is not illegal, Dinkla said that the act of activating bright lights near another vehicle violates Iowa Code section 321.415.

Whenever the driver of a vehicle follows another vehicle within four hundred feet to the rear, except when engaged in the act of overtaking and passing, the driver shall use a distribution of light permissible under this chapter other than the uppermost distribution of light

Iowa Code Chapter 321.415

The American Civil Liberties Union (ACLU), has stepped in numerous times across the country representing individuals concerning this subject. In a particular ruling for Missouri stemmed from a 2013 case in Ellisville when a driver received a citation for flashing his headlights “to notify motorists of a radar set up ahead.”

“The police cannot retaliate against drivers who have done nothing wrong and are simply exercising their right to communicate with other drivers,” says Jeffrey A. Mittman, executive director of the ACLU of Missouri.

Basically, every state has different rules regarding flashing lights as a warning. However, with the Supreme Court ruling in Spence v. Washington, it’s safe to say outdated municipal ordinances about this issue don’t hold water.