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 Jersey, the act of headlight flashing does not have a specific statute governing its use. However, drivers may be cited under general traffic laws if the action is deemed inappropriate or unsafe. For instance, New Jersey law requires that drivers use their headlights from 30 minutes after sunset to 30 minutes before sunrise, during periods when visibility is 500 feet or less, or during adverse weather conditions. If a driver flashes their headlights outside of these conditions, it could potentially be seen as a misuse of headlights. Additionally, New Jersey law prohibits the use of high beams within 500 feet of an oncoming vehicle, so flashing high beams could result in a citation if it occurs within this distance. While headlight flashing could be interpreted as a form of communication, and there have been instances where the First Amendment has been argued in defense of headlight flashing, New Jersey courts would consider the specifics of each case, including the safety implications and the intent behind the flashing, when determining the legality of the action. It is important for drivers to be aware of the potential for being cited under related traffic laws when engaging in headlight flashing.