If someone flashes their lights at you, they’re usually telling you to slow down because there is a police officer with a speed camera or radar gun ahead, or there may be a stationary speed trap camera car close by.

    • Flashing your headlights can help warn other drivers of your intent
    • Drivers will often flash their lights to warn other road users of police presence
    • Rules vary between jurisdictions

    The other reason someone may flash their lights is to tell you that you don’t have your lights on. 

    But is it illegal to do so? Depends where you do it.

    In New South Wales there is no specific law around flashing your lights to warn other road users, but if you are found to do so and found to “dazzle” another road user, or use your high beam lights within 200 metres of another vehicle, you could be fined, and demerit points may apply.

    However, a police officer we spoke with said he was “all for it”, and that “if it helps slow people down, it could save a life”. Seems like terrific logic.

    In the Northern Territory, road users are actively encouraged to flash their headlights when interacting with Road Trains (multi-trailer trucks). If being overtaken by a Road Train, the Road Safety Rules and Conditions website states: “When the road train has passed, flash your headlights to let the driver know that it is safe to move back in.”

    According to the RACV, Victoria is strict when it comes to warning other road users about speed cameras, specifically. That motoring club reports that “you’re not allowed to flash your headlights to warn other drivers about a mobile speed camera”, but we couldn’t find any specific law stating as much in the Victorian Road Safety Rules 2017.

    “Drivers may switch their headlights to high-beam briefly to warn a vehicle ahead that you’re about to overtake. Using headlights on high beam isn’t allowed within 200m of an oncoming vehicle or a vehicle travelling in the same direction ahead of you as it can dazzle the other driver.

    The rules are of the same mindset in Queensland: “You must not have your headlights on high beam if another vehicle is closer than 200m to you – this includes when you are following someone and when they are driving towards you. 

    “You may flash your headlights briefly before overtaking another vehicle, but make sure they do not dazzle other road users. You may be fined for incorrectly using your high beam lights.”

    In Tasmania, for example, the law states that it is illegal to “use high-beam headlights within 200 metres of a moving vehicle”, and if you do so, you could be hit with a $181 fine and one demerit point. 

    The Australian Capital Territory has similar legislation: “The driver of a vehicle must not use the vehicle’s headlights on high-beam, or allow the vehicle’s headlights to be used on high-beam, if the driver is driving: (a) less than 200m behind a vehicle travelling in the same direction as the driver; or (b) less than 200m from an oncoming vehicle.” A penalty of up to $5500 may apply if taken to court.

    However, in the ACT “the driver may briefly switch the headlights from low-beam to high-beam immediately before the driver begins to overtake the vehicle”, so long as the lights are not used to “dazzle other road users”.

    South Australia doesn’t state any such rule around flashing your headlights, other than to say that you “can momentarily flash your headlights on high beam to indicate to another driver that you intend to overtake”. 

    In Western Australia, “High beam lights are not permitted: if you’re driving less than 200m behind a vehicle; or if an oncoming vehicle is less than 200m or has its headlights dipped.”

    Not intended as legal advice. Check with the relevant roads authority in your state or territory.

    Matt Campbell
    Matt Campbell is a Senior Contributor at CarExpert.
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