Is it Legal To Flash Your Headlights To Warn About Speed Checks?

You're driving home in the afternoon and on the way back you spot an unmarked cop car parked by the side of the road doing speed checks. Instinctively, you flash your headlights to warn oncoming drivers about the speed trap ahead. Seems normal enough, but is this act of goodwill legal?

Headlights image from Shutterstock

Flashing your high beams to warn others of hazards and police on the road ahead is an unspoken road etiquette that most Australian drivers know about. While there aren't any specific laws nationally that deal with flashing headlines to alert others, there are strict rules in place when it comes to the use of high beams.

As stipulated in the Australian Road Rules (2006) Section 218 for the use of high beams:

(1) 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 200 metres behind a vehicle travelling in the same direction as the driver, or (b) less than 200 metres from an oncoming vehicle.

When you flash your headlights as a warning, it usually occurs within the distance limits stipulated in the legislation so, technically, it is illegal. In fact, the Queensland police has used this rule to issue fines and incur demerit points to drivers who flash their high beams to warn others of speed camera and law enforcement vehicles ahead.

Meanwhile, in Victoria, police are fine with drivers flashing their headlights to warn others of speed cameras. So the law on high beam use is adapted by law enforcement agencies in different states accordingly but police are technically allowed to penalise you if you do flash your headlights as a warning to other drivers.

Did you just catch yourself wondering if something was legal or not? Let us know and we may be able to answer it in our next Is It Legal? feature.


    Flash them just as you are passing them. Enough to notice, doesn't shine in their eyes.

    In my younger days I was a bit enthusiastic and flashed someone about 5 times. When they got closer it was a cop car. They just kept going. Tasmania.

    I do it all the time if I see a car speeding or hooning , it slows them down for a bit thinking there is a copper ahead. Dont need idiots on the road.

      Yeah, same here! Funny watching them slow down thinking there is police a head when they're isn't.

        Dick move

          Why be a stooge.

        i am you, and he is me

      I had a chat with an off duty highway patrol Officer during Xmas.
      He doesn't mind people flashing lights to warn people, He said, "they are doing our job for us, getting people to slow down and not dying."

      So you are setting yourself up as arbiter of others behaviour. Don't need "Holier than thou" people on the road either

    but police are technically allowed to penalise you if you do flash your headlights as a warning to other drivers.

    See, this is where it gets dodgy for me. I don't normally believe in the term 'revenue raising', but if something is 'technically' allowed, then it should be clarified. It either is or it is not. Because that means the decision can be abused. If I turn my low beams on, off, on, off etc, then I am not breaking the law. But, high beam, sure I am breaking the law. But if I do low beam, why should I be penalised, for not breaking the law?

      Enh. I figure it's probably like jaywalking. You very rarely see enforcement teams out and about, outside of a few hotspots known for causing problems with traffic.

      I am pretty sure driving without your headlights on after dusk is a penalty in NSW too?

      Which means turning off your headlights could land you with a fine also?

    As stipulated in the Australian Road Rules (2006) Section 218 for the use of high beams:
    @spandaslui - that link points to repealed NSW legislation, however appears to still be active in SA.
    NSW has expanded their definitions under 218 and may now to incorporate @pinchie 's use case of using regular lights to "flash"

      Hi robb.

      Thanks for pointing that out. Have looked at Road Rules in other states and section 218 on high beams still apply, including for Victoria:$FILE/09-94sr003.pdf

      Bottom line is, the rule still exists but can vary state-by-state.

      Hope this helps!



    you'd be lucky to see a queenslander flash their lights at you, bloody maniac drivers all speed, you'd think that they would, but they don't

      Having spent some time there, they sure do. Usually it's because you're only doing 20 over the speed limit in front of them and they're doing 40 or more over.

      You must be from VIC or SA.. I'm originally from NSW (Sydney) and everyone drives so S L O W Up here in QLD...


        I'm from SA, and QLD drivers crawl around the roads like old grannies.

        It seems QLD drivers can't be bothered paying attention to the speed limit signs, and just drive at 50 km/h or less... everywhere, even when the speed limit is 60, 70 or 80. Do this in the USA and you will be fined for obstructing the traffic.

        Most people in Brisbane drive the speed limit plus or minus 5km/hr. The occasional outliers will be 15-20km/hr over or under. Other cities can't say.

    So what if I flash my lights to warn another driver of a hazard (ie not a speed trap) in the road ahead?
    If this rule still applies, then I should just let them plow into that herd of cattle around the next bend?

    That's what technically means here. You are not legally allowed to flash your headlights. The law is in place to stop you blinding other motorists. Like most laws or can be applied to unindented things like completely safe flashing discussed here. Also turning your lights on and off I.e. not high beam is completely legal

    I never flash my headlights to warn motorists about speed cameras. My reasons are that if a speeding motorist avoids a speeding fine due to my actions they would likely speed up again. After doing so, they are at more of a risk of hitting a pedestrian, another car or a tree. I'd rather the get the fine and learn a lesson than potentially kill someone due to my intervention.

      I am the opposite to you then.
      I tend to speed after passing a speed trap because they really piss me off. Could be out stopping crimes instead of taking $190 of my hard earned.
      And yes you can always reply with "do the crime, do the time", but is it really a crime? I drive to conditions. If I come off the highway and haven't reached 60 yet its not really a crime against humanity is it? I still go less than 40 near some schools.

        States have to raise money one way or the other; road fines are, in a way, a stupidity tax. As long as you pay less in road fines than the average in your state, you're probably getting a discount on your tax.

    There's a temporary highway sign near my house at the moment which alternates saying: "police enforcing speed", and "high risk area".
    My question is: high risk of what?
    The only 2 bad accidents in the immediate area within the last 2 years were elderly drivers screwing up.

      I love the Police Enforcing Speed signs, always make me laugh driving to Melbourne. "I'm sorry officer, the sign said you were enforcing speed so I sped up when I saw your lights".

    Most times ya more than 200m away. I also flash my lights for fallen trees and other road hazards..

    Light sensitivity is relative. Hi-beams are only blinding at night because your eyes (irises) are open wider and are pulling in more light. So this law should really only apply to night driving.

    On top of that, in most halogen headlights, the bulbs come up their full brightness over about half a second or so. A flash is usually only a quarter of a second, so they are not at full brightness. They will only dazzle you if they are held on.

    In short, any officer booking you for use of your high beams in this manner is probably having a bad day.

    Couldn't care less what the plod think, I will always warn drivers of wallet targeting thievery.

    I'm Curious how thing plays out comparing to "Flashing (Headlights) Protected by First Amendment ... " in the States

    Don't we have something similar?

    I remember Carl O'Callaghan (WA Police chief) saying that WA police don't care if people flashing their lights, and actually encourage it, if it means people stop speeding.

    I don't flash anyone. If you are stupid enough to speed, you are stupid enough to deserve the fine. The roads are already full of incompetent people who cannot obey the road rules (but claim they are driving to the conditions). Let the stupids get fined, give their money to the state (when they don't have to), and eventually they gain 12 demerit points so they are off the roads for awhile. 1 less stupid person on the road.

    Sweet, so long as I use my low beams in QLD, there's nothing to worry about. I hate the Police and their sneaky revenue raising tactics, they always put cameras on long flat straights, bottom of hills etc. There is a thing called safe speeding, I do it everyday and have never been involved in an accident . Slow incompetent drivers cause accidents, sitting in the outside lane blocking people from overtaking!. Now they're the ones who should lose their license!

    Last edited 11/02/16 9:50 pm

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