Headlight flashing
Headlight flashing is the act of either briefly switching on the headlights of a car, or of momentarily switching between a headlight's high beams and low beams, in an effort to communicate with another driver or drivers. The signal is sometimes referred to in car manufacturers' manuals as an optical horn, since it draws the attention of other drivers.
The signal is intended to convey a warning to other drivers of road hazards.
History
Headlight flashing might have come into more common use as a means of attempting driver-to-driver communication by the mid-1970s, when cars began to come with headlight beam selectors located on the steering column—typically activated by pulling the turn signal stalk—rather than the previous foot-operated pushbutton switches. The signal stalk configuration was later wired to permit the momentary activation of the high beams regardless of whether the headlamp switch was turned on or off. Motorcycle headlamp modulators automatically oscillate the intensity of the headlamp in an effort to make the motorcycle more conspicuous to other drivers.Uses
Headlight flashing attracts attention, and so can be considered the visual equivalent of blowing the horn. Indeed, some car owner's manuals identify headlight control on the steering column as the "optical horn". Like the horn, it has many uses:- Letting other drivers know of one's presence.
- Acknowledging the presence or actions of other drivers.
- Signaling that the flashing driver is yielding the right of way, for example at an intersection controlled by stop signs.
- Warning other drivers of road dangers, such as crashed cars or police speed traps.
- Giving thanks to other drivers. For example, when one is warned of police presence, it is sometimes considered courteous to flash back.
- Informing other drivers of problems with their car, such as headlamps left off after dark, burned out or misaligned lights, or misuse of high beam rather than low beam in traffic; or to berate a driver who poses a risk to traffic. Headlight flashing coupled with blowing the car's horn can help clear deer from a driver's path.
- Indicating the intention to overtake another driver, or to signal a driver who has just overtaken that they can now return to the original lane. Flashing can request or insist that a leading driver speed up or change lanes to get out of the way of a faster following driver.
Some drivers attempt to communicate "I will continue my current behavior!" when flashing their headlights. For example, if such a driver flashes his or her headlights while slowing down, they intend to communicate to another driver who is waiting to merge in traffic: "Go on, I will let you merge!" On the other hand, if such a driver keeps his or her current speed and flashes headlights, they intend to communicate "Stay back, I am not slowing down!"
Effectiveness and ambiguity
Headlight flashing as an effective mode of driver communication has been questioned, and researchers have found the ability of drivers to communicate with one another is about the same as the communication abilities among insects.Flashed headlamps can have ambiguous or contradictory meanings, with no way for the observing driver to tell for sure what the flashing driver is trying to say. It may mean, for example, that the flashing driver intends to yield the right of way, or instead that they intend to take it. Misinterpretation of the flashing driver's intent can cause crashes.
Legality and meaning
Australia
Headlight flashing to warn drivers of traffic enforcement cameras is illegal in the state of Queensland, carrying a $30 fine and one demerit point, or a $1500 fine if the fine is unsuccessfully challenged in court. Officers may either fine a driver for improper use of headlights, or may even arrest and prosecute for hindering police.In the state of South Australia, headlight flashing by regular drivers for any reason is illegal, except in emergency purposes and immediately before overtaking.
In Victoria, Traffic Superintendent Dean McWhirter has said he is happy for motorists to flash their lights to warn other motorists they were approaching a speed camera in 2013.
Bangladesh
Headlight flashing is common in Bangladesh, where roads are sometimes narrow and lane discipline is lax. It is done by large vehicles such as buses or trucks to alert smaller, more maneuverable vehicles to their presence and to encourage them to make way, for example by moving to the side of the road.Canada
In Ontario, the Highway Traffic Act does not prohibit "flashing head beams". Some have brought tickets to court, claiming the law only regulates the use of alternating lights in an attempt to impersonate emergency and law enforcement vehicles, and not a driver's manually flashing his car's headlamps to communicate with other drivers. The section that deals with alternating headlights in Ontario is Section 169 of the Highway Traffic Act. It is an offence to improperly use high-beams at night, which is dealt with by way of section 168 of the Highway Traffic Act.India
In India, headlight flashing has different meanings to different drivers in different places and situations, though frequently means a request to give way. Despite government attempts to curb misuse, the high beam is frequently used as the standard for night time driving by a substantial number of vehicles, given the proportionately poorly lit roads and highways.Tamil Nadu law explicitly prohibits the use of headlight flashing; the Tamil Nadu Motor Vehicle Rules state that ‘lights are not to be used or manipulated in a manner that causes danger or undue inconvenience to a person by dazzle’, under Section 495.
Jamaica
On some occasions, motorists who flashed their headlights to warn of police activity have unwittingly helped fugitives evade police. In 2008, one of Jamaica's most wanted men went around police checkpoints which had been set up on his most likely routes after a driver had flashed his headlights to warn of police ahead. Drivers were warned that flashing headlights may result in "unwittingly facilitating criminal activity".Philippines
Headlight flashing is understood and practiced differently in the Philippines compared to the usual global context. Drivers in the Philippines use headlight flashing to inform vehicles and pedestrians of their presence, which may mean simply yielding to others or asserting one's right of way. Thus, vehicles and pedestrians may proceed with crossing the road or are obliged to stop and give way to the other vehicle that has flashed its headlights. This has become the norm that in crossroads, that whoever flashed their headlights first, gets to safely cross first. Moreover, it has something to do with performing overtakes. A vehicle that wishes to overtake a slower moving one in front of it, may flash its headlights a few times to signify the intent to overtake.United Kingdom
Though not all of its rules represent law, the Highway Code states "Only flash your headlights to let other road users know that you are there. Do not flash your headlights in an attempt to intimidate other road users".Headlight flashing in the United Kingdom is often used as a signal that the driver flashing you is offering to let you go first. Such use is however strongly discouraged because it can lead to accidents where the driver flashing has not seen the approach of another road user. Using it to indicate that you are coming through and the other driver must wait, could lead to an accident.
Drivers should also be aware of the so-called "Flash-for-Cash" scam, in which criminals flash their lights to let other drivers out of a junction, then crash into them on purpose in order to make fraudulent insurance claims for damage and whiplash injury.
United States
In the United States, although the legality of headlight flashing varies from state to state, a federal court ruled that flashing headlights was a constitutionally protected form of speech, issuing an injunction prohibiting a police department from citing or prosecuting drivers who flash their lights to warn of radar and speed traps. On 23 April 2019, another court ruled that headlight flashing may be protected by the First Amendment. Two state circuit courts have also ruled that headlight flashing is protected activity.Some states consider that drivers have a First Amendment right to flash their headlights. In other states, law enforcement officers may give citations for headlight flashing under laws prohibiting a person from obstructing a police investigation, laws prohibiting a person from having flashing lights on their vehicle, or laws prohibiting shining a vehicle's high beams at oncoming traffic. The specific language of each law varies by state along with courts' holdings on whether their respective laws prohibit headlight flashing. Additionally, although not legally binding, the state driver's manual of some states suggests flashing high beams under specific scenarios.