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 New York, headlight flashing is not explicitly prohibited by state law, but it can be subject to interpretation under various traffic regulations. For instance, New York Vehicle and Traffic Law Section 375 (3) requires that drivers use their headlights from 30 minutes after sunset to 30 minutes before sunrise, during poor visibility, or when windshield wipers are in use. However, this law does not directly address headlight flashing. Additionally, Section 375 (3-a) prohibits the use of high beams within 500 feet of an oncoming vehicle, which could be relevant if headlight flashing involves switching from low to high beams in the presence of oncoming traffic. While headlight flashing could be seen as a form of communication, potentially protected under the First Amendment, it could also be interpreted as aggressive driving or a distraction to other drivers, depending on the context. New York does not have a specific statute against headlight flashing to warn of speed traps, and court rulings have varied on whether such actions are protected speech. Therefore, while headlight flashing is not outright illegal in New York, it could lead to a traffic stop or citation if it is deemed to violate other traffic laws or is considered to be aggressive or hazardous driving.