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 Pennsylvania, headlight flashing is not explicitly regulated by a specific state statute that addresses the practice in its entirety. However, drivers in PA should be aware that flashing headlights could be interpreted under various traffic laws. For instance, Title 75 (Vehicle Code) of the Pennsylvania Consolidated Statutes, Section 4306, states that high beams must not be used within 500 feet of an approaching vehicle, which could be relevant if a driver is flashing their high beams at oncoming traffic. Additionally, the use of flashing lights is generally restricted to emergency vehicles and certain service vehicles under Section 4571. While headlight flashing could be seen as a form of communication, potentially protected by the First Amendment, it could also be construed as a distraction or aggressive driving behavior under certain circumstances. Police officers may issue tickets for reasons they deem appropriate, such as aggressive driving or obstructing an investigation, and such incidents can lead to further charges if a traffic stop reveals additional violations like DUI/DWI. Drivers who receive tickets for headlight flashing have the right to challenge the citation in court, where the interpretation of the First Amendment and other relevant laws will be considered.