Headlight flashing is the act of a driver flashing their headlights at an oncoming driver by briefly turning the headlights on or off, or from high beam to low beam, or low beam to high beam. There is no set or clear message transmitted by headlight flashing, but it often means the driver who flashes their headlights believes the oncoming driver’s headlights are inappropriately on high beams or are not turned on or illuminated when they should be.

Headlight flashing may also be intended to convey other messages, such as warning another driver of the flashing driver’s presence; telling another driver to proceed in front of the flashing driver (yielding the right of way); or warning an oncoming driver of danger ahead—which may include a deer or other animal in the road, an automobile wreck, or a police officer hidden from view who is checking the speed of passing drivers and issuing speeding tickets (a speed trap).

Police officers have sometimes issued traffic tickets to drivers for headlight flashing, and in some instances a traffic stop for headlight flashing has led to more serious charges and an arrest for DUI/DWI, for example. Tickets for headlight flashing are often issued based on an alleged violation of a municipal ordinance or a state statute that prohibits:

• high beam headlights within a certain distance (500 feet, for example) of an oncoming driver;

• aggressive driving;

• having flashing lights on a vehicle; or

• obstructing a police investigation.

Drivers who have received tickets for headlight flashing have sometimes challenged the ticket—or the traffic stop that led to an arrest and additional charges—on the ground that headlight flashing is a communication protected by the First Amendment to the United States Constitution.

Laws and ordinances vary from state to state and among cities and towns (municipalities), and state and federal courts have arrived at different conclusions when applying the First Amendment and other laws and ordinances to traffic tickets or stops based on headlight flashing.

In Minnesota, headlight flashing is not explicitly prohibited by state law, but it can be indirectly related to various traffic regulations. For instance, Minnesota Statute 169.61 prohibits the use of high beams within 1,000 feet of an oncoming vehicle or within 200 feet when approaching a vehicle from behind. While this statute does not directly address headlight flashing, it does regulate the appropriate use of high beams, which could be implicated if a driver is flashing their headlights to signal that another driver's high beams are on. Additionally, Minnesota does not have a specific statute against aggressive driving that encompasses headlight flashing. However, flashing lights are generally reserved for emergency vehicles and certain service vehicles under Minnesota Statutes 169.64 and 169.59, and unauthorized use could potentially be cited under these statutes. Regarding the First Amendment defense, while there is no specific Minnesota case law on headlight flashing as protected speech, courts in other jurisdictions have recognized headlight flashing as a form of communication that may be protected by the First Amendment. Minnesota drivers should be cautious when flashing headlights, as it could be interpreted as a violation of headlight use regulations or could inadvertently lead to a traffic stop and further scrutiny.