If you’ve ever flashed your high beams to warn someone about a radar car up ahead, you’re not alone.
The “tap the lights” signal started as a neighborly heads-up. This simple, low-tech communication predated smartphones and map apps.
So, is that friendly flick of the lights legal or not? Read on to find out.
Why drivers flash their headlights
Most people flash their headlights to quickly share a message to oncoming drivers: slow down, your high beams are on, your lights aren’t on, or there’s something on the road ahead you should know about.
The “speed trap flash” is usually a quick on-off of the high beams aimed at an oncoming driver so they’ll check their speed or be extra cautious. For drivers in big rigs or RVs who have slower stopping distances and wider turns, the signal can be a useful early warning to reduce speed safely and avoid trouble.
How courts and police respond
U.S. courts and municipalities have split on the issue of light tapping. Several federal and state court decisions have treated flashing headlights as expressive conduct that can be protected by the First Amendment.
A federal district court in Missouri permanently stopped a city from ticketing drivers who flashed lights to warn of speed traps. They concluded the act was communicative speech rather than a traffic violation. Other federal opinions have reached similar conclusions or carefully limited enforcement.
At the same time, law enforcement in other places has cited people for obstructing police activity or for lighting equipment violations when they flash. The result is a patchwork of enforcement: protected speech in some jurisdictions, ticketable conduct in others.
What’s an RVer to do?
A few states have headlight/dimming rules that can make flashing risky if you do it within certain distances or in certain ways. For example, some vehicle codes require drivers to dim high beams when approaching another vehicle within specified distances (commonly 300 to 500 feet). Officers can apply this code to ticket the improper use of high beams or distracting other drivers.
North Dakota’s vehicle code and similar provisions in other states expressly limit flashing high beams when an oncoming vehicle is within a certain distance. In some cases, those statutes have been used to support traffic stops.
Arizona and Michigan both have dim-your-high-beams provisions that officers might rely on when they believe flashing blinded another driver or violated lighting statutes.
Because laws vary and enforcement is local, the safest assumption is that could-be-ticketed behavior exists in some states. If you travel state-to-state in an RV, this patchwork matters.
Note to RVers
RVers cross county and state lines often, driving vehicles that take longer to slow and that make them more visible targets for speed enforcement (narrow shoulders, rural highways, and lower speed limits in tourist areas).
An unexpected ticket or traffic stop can throw off campground check-ins, reservations, and trip budgets. Plus, pulling off (and back onto) a highway in an RV is more of a hassle than in a sedan.
Knowing local rules around headlight use reduces the chance of surprises and keeps trips running smoothly.
To flash or not to flash?
If you flash to warn, you may still get pulled over. An officer could view the act as interfering with an investigation, use lighting statutes to justify a stop, or interpret the flash as aggressive or dangerous (especially if it actually blinds another driver). Momentary flashes can startle drivers and cause overcorrection. This is especially dangerous for large rigs when roads are narrow.
In areas that prohibit flashing lights except for emergency or authorized vehicles, a citation could be assessed under local codes even when your intent was benign.
Finally, flashing is not a substitute for safe driving. If a person slows from a flash but was already driving unsafely, the flash could shift responsibility without fixing the risk.
Bottom line
Flashing headlights to warn about speed traps is common and, depending on where you travel, may be protected speech or may trigger a ticket under lighting or obstruction laws.
Because laws and enforcement differ between states and even cities, RV drivers who crisscross the country should play it safe. Drive responsibly, slow down when conditions require it, and avoid relying on headlight flashes as a warning to others.
If you want to be helpful on the road, use safe, predictable driving behavior first, like signals and steady deceleration. These are more reliable and less likely to land you in front of a judge.
Do you think tapping or flashing headlights should be legal or illegal in every jurisdiction? Tell us in the comments below.
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RVT1244
I stopped flashing oncoming traffic regarding police ahead of them because, personally, it’s their responsibility (as it is mine) to obey traffic laws. However, I will flash my headlights to warn oncoming drivers their lights aren’t on or their high beams are blinding others.
I only flash my lights when there is a hazardous condition ahead of oncoming traffic. Usually deer or a disabled vehicle over a hill or blind turn. In daylight I’ll use my high beams, at night I turn my headlights off briefly. The number and speed of flashes indicates the severity of the problem.
Many argue that moving violations are all about public safety, but let’s at least acknowledge the fact that these violations collect lots of revenue for municipalities and states. The city of Denver collected over 44 million last year. A small town near me setup speed traps on a freeway adjacent to it that collected half of the towns revenue until enough people complained to the state and it was shut down. There’s a big incentive to use traffic violations for revenue generation.
Define speed “trap.” One only gets “trapped” if they are speeding, right?
The Supreme Court ruled that this type of ‘incentive – money or ticket count/competition’ is illegal. Does it still happen? Probably. But I personally want speeders to pay the piper.
About the only time I flash is if oncoming vehicles are not using headlights when they should be – so dusk or fog. Those lights are not for the driver of that vehicle to see, but for oncoming traffic to see them.
Some federal courts have held that flashing headlights to warn drivers of speed traps or to communicate is expressive conduct protected by the First Amendment.
You speed – I will not warn you of any speed traps. I’m going to let you get caught. Let your insurance increase. Let you get mad at the system. Blame everyone but yourself. You know…the America way. 😉 I use to warn people but that was when people were more friendly.
A none existent problem looking for a solution!
Must be slow article day at RVtravel.com!
The ONLY time I flash an oncoming car is if their high beams are on or no lights at all. Beyond that you’re on your own.
I have but don’t flash my headlights for speed traps anymore. I finally figured out if I could see the trap in time any other alert driver should too. But taking it further I also use Wyse and notice that the police reported ahead is used often. How is that different than using other forms of communication, like flashing your headlight. If you are enforcing one but not the other, is that right?
I will continue to flash to warn of police for oncoming traffic.
Because “No one is above the law,” right? Those nasty police doing their jobs enforcing the law. Shame on them! 🙄
53 years of commercial driving and still give heads up. Here comes the old guy.We used to use hand signals back before interstate highway. Ok I’m going back to my nap. Drive safe.
OK so….not wearing a halo, no angel wings, no Boy or Girl Scouts, teacher’s pets, or Sunday School Stars here…lol. Just people living life. I do warn people, but not with high beam flashing, I just flash the headlights off and on quickly.
Mischief managed 🙂
What about flashing your lights to let the truck passing you know that it is clear to move back into your lane? Or to thank the one that let you in? My Smart Steering Wheel has buttons for both – the ICC Flash function.
Whose side are we on, anyway? We are in great danger in America of no longer being a law-abiding nation. Whether or not we like the politicians or the laws they make, anarchy will always be worse than law and order.
I used to always drive sporty cars, so truck drivers always let me know, which I appreciated. I don’t see people doing it as much anymore. Often times, people also flash because a car or wreck is ahead so one can be ready for that.
I was taught to flash your headlights on 2 lane roads to indicate the on coming driver needs to dim their lights. I was actually fined because I didn’t dim my lights to an oncoming police vehicle.
Up here on #97 along the Columbia River it is a great help to warn oncoming drivers of those pesky Big Horn Sheep, just waiting to make a bunch of people have a very bad day. I’ll keep flashing.
I’ve had the misfortune of being attacked by 3 deer over the years. The score is Winnebago -0- Deer 3. Good thing I have a real steel bumper. Two of those deer were at the same time. One on the left corner and the other on the right, They wandered away and as I looked in my side mirror one of them gave me the “Hoof.”