# Legalities of warning oncoming traffic of radar traps? **URL:** \ **Category:** Factual Questions\ **Created:** [March 29, 2007, 5:07pm UTC](https://boards.straightdope.com/t/legalities-of-warning-oncoming-traffic-of-radar-traps/397999 "2007-03-29T17:07:09Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![DSYoungEsq](https://avatars.discourse-cdn.com/v4/letter/d/c6cbf5/32.png) [@DSYoungEsq](https://boards.straightdope.com/u/DSYoungEsq)\ **Post date:** [March 30, 2007, 2:43am UTC](https://boards.straightdope.com/t/legalities-of-warning-oncoming-traffic-of-radar-traps/397999/21 "2007-03-30T02:43:22Z")
[QUOTE=RyJae] [http://www.doylestownpa.org/police/html/askacop\_edition\_3.htm](http://www.doylestownpa.org/police/html/askacop_edition_3.htm) How I read it , it is not illegal to do warning other drivers. It is a pull over offense, malfunctioning headlights. In PA that is. [/QUOTE] In actuality, the relevant statute is: [Title 75 §4306 (Pennsylvania Vehicle Code)](http://www.dot10.state.pa.us/pdotforms/vehicle_code/chapter43.pdf) > [@](#): > > (June 25, 1987, P.L.30, No.13, eff. 60 days) > § 4306. Use of multiple-beam road lighting equipment. > (a) Approaching an oncoming vehicle.–Whenever the driver of a vehicle approaches an > oncoming vehicle within 500 feet, the driver shall use the low beam of light. > (b) Approaching a vehicle from rear.–Whenever the driver of a vehicle approaches another > vehicle from the rear within 300 feet, the driver shall use the low beam of light. > (c) Exception.– > (1) An emergency vehicle which is equipped with a flashing headlamp system that > conforms to regulations promulgated by the department shall be exempt from the provisions of > this section only when the vehicle is being used pursuant to the provisions of section 4571(e) > (relating to visual and audible signals on emergency vehicles). > (2) Nothing in this section shall limit drivers from flashing high beams at oncoming > vehicles as a warning of roadway emergencies or other dangerous or hazardous conditions ahead. > (Dec. 18, 1992, P.L.1411, No.174, eff. 60 days; Dec. 21, 1998, P.L.1126, No.151, eff. imd.; June 26, > 2001, P.L.734, No.75, eff. 60 days) The use of a high beam to signal an officer ahead would not fall under the exemption for warning of dangerous or hazardous conditions ahead. ---
**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\ **Post date:** [March 30, 2007, 12:53pm UTC](https://boards.straightdope.com/t/legalities-of-warning-oncoming-traffic-of-radar-traps/397999/22 "2007-03-30T12:53:09Z")
Recap: Nobody is disputing the original question, and a sign is not illegal as far as anybody posting knows. The cops will get you for different reasons than warning drivers, if you are driving a car, because it violates other driving regulations. ---
**Author:** ![Balthisar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/balthisar/32/2825_2.png) [@Balthisar](https://boards.straightdope.com/u/Balthisar)\ **Post date:** [March 30, 2007, 1:00pm UTC](https://boards.straightdope.com/t/legalities-of-warning-oncoming-traffic-of-radar-traps/397999/23 "2007-03-30T13:00:58Z")
[QUOTE=DSYoungEsq] In actuality, the relevant statute is: [Title 75 §4306 (Pennsylvania Vehicle Code)](http://www.dot10.state.pa.us/pdotforms/vehicle_code/chapter43.pdf) [/QUOTE] Yeah, but that statute refers to _the use_ of low beams versus high beams, not necessarily the flash-to-pass function of your lights. Although not codified right there, the use of an intermittent function is not the same as the use of high beams, because you’re not using high beams; you’re using an intermittent function. Or not? > [@Q.E.D.](#): > > Day or night? If it’s day and your headlights are off, when you flash your headlights on most cars, the taillights flash too. At night, well, it’s perfectly obvious even from well behind the car doing the flashing. Huh? If you turn your lights on and off, your tail lights will certainly come on. I can’t imagine there are still a significant number of cars on the road that don’t have a flash-to-pass function that simply activates the lamps on an intermittent basis. ---
**Author:** ![SuaSponte](https://avatars.discourse-cdn.com/v4/letter/s/67e7ee/32.png) [@SuaSponte](https://boards.straightdope.com/u/SuaSponte)\ **Post date:** [March 30, 2007, 1:19pm UTC](https://boards.straightdope.com/t/legalities-of-warning-oncoming-traffic-of-radar-traps/397999/24 "2007-03-30T13:19:39Z")
[QUOTE=Frylock] I’m not following you. By saying that, don’t you arguably thereby _enter into_ a conspiracy with that stranger? I think you could fill in the details of your story to make it come out different ways, but just as you’ve told it, my intuition is that you’re doing something wrong when you warn the criminal. [/QUOTE] Your answer assumes that the driver providing the warning is aware that the approaching drivers are acting illegally, _i.e._ actually speeding. Personally, unless the approaching car is traveling at a truly excessive speed, I can’t tell whether the cars are speeding. So, usually, when I flash my high beams, I’m not aiding someone in committing an illegal act, or in avoiding apprehension for having committed an illegal act. Instead, I’m warning the approaching drivers not to commit an illegal act. That is high-minded civic virtue. 🙂 It is certainly not a conspiracy under any interpretation of penal law of which I am aware. Sua ---
**Author:** ![DSYoungEsq](https://avatars.discourse-cdn.com/v4/letter/d/c6cbf5/32.png) [@DSYoungEsq](https://boards.straightdope.com/u/DSYoungEsq)\ **Post date:** [March 30, 2007, 1:52pm UTC](https://boards.straightdope.com/t/legalities-of-warning-oncoming-traffic-of-radar-traps/397999/25 "2007-03-30T13:52:45Z")
[QUOTE=Balthisar] Yeah, but that statute refers to _the use_ of low beams versus high beams, not necessarily the flash-to-pass function of your lights. Although not codified right there, the use of an intermittent function is not the same as the use of high beams, because you’re not using high beams; you’re using an intermittent function. Or not? Huh? If you turn your lights on and off, your tail lights will certainly come on. I can’t imagine there are still a significant number of cars on the road that don’t have a flash-to-pass function that simply activates the lamps on an intermittent basis. [/QUOTE] Balthisar, you fail to grasp the simplicity of this because you think logically, but not from the right viewpoint. 😉 If you flick or flash your headlights to the bright beams, you are using the bright beams. Period. End of discussion. The length of time you used them is irrelevant. Ergo, flashing the brights within 500 feet of an oncoming car is a violation of the law. Now, if you had your lights OFF, and you turned them on and of and on and off to warn someone, that would be different, assuming you didn’t use the bright beams. But almost all of the mechanisms for flashing the lights (such as, for example, pulling toward you on the turn indicator lever) will flash the brights if your lights are off in the first place. So, to sum up, if you flash the brights, you violate the law. If you flash the low-beams, you don’t violate THAT statute. Not saying there wouldn’t be others they could trot out at need. 😛 ---
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [March 30, 2007, 1:54pm UTC](https://boards.straightdope.com/t/legalities-of-warning-oncoming-traffic-of-radar-traps/397999/26 "2007-03-30T13:54:45Z")
[QUOTE=SuaSponte] Your answer assumes that the driver providing the warning is aware that the approaching drivers are acting illegally, _i.e._ actually speeding. [/quote] 😕 I didn’t say anything about anyone driving any cars… -FrL- ---
**Author:** ![Gfactor](https://avatars.discourse-cdn.com/v4/letter/g/9de053/32.png) [@Gfactor](https://boards.straightdope.com/u/Gfactor)\ **Post date:** [March 30, 2007, 2:06pm UTC](https://boards.straightdope.com/t/legalities-of-warning-oncoming-traffic-of-radar-traps/397999/27 "2007-03-30T14:06:59Z")
> [@](#): > > a Williamson County judge dismissed the city of Franklin’s case against a man who flashed a warning and was charged and found guilty of interfering with a police officer’s performance of duty. He appealed. > > Judge Russ Heldman dismissed the city’s ruling that Harlie ‘‘Bill’’ Walker, 75, violated a Franklin ordinance Aug. 14, when he flashed his lights at oncoming traffic to let drivers know there was a police car ahead. [http://www.tennessean.com/local/archives/03/10/41877517.shtml?Element\_ID=41877517](http://www.tennessean.com/local/archives/03/10/41877517.shtml?Element_ID=41877517) > [@](#): > > Motorists are allowed to flash their headlights to warn oncoming drivers about a speed trap, an appeals court ruled last week. > > A two-judge panel ruled that Susan R. Luptak of Jackson violated no state laws when she flashed her headlights to warn an oncoming motorist about a speed trap. [http://groups.google.com/group/nyc.general/browse\_thread/thread/f821eb6ba6bc1bf5/2378e78a012cf361%232378e78a012cf361](http://groups.google.com/group/nyc.general/browse_thread/thread/f821eb6ba6bc1bf5/2378e78a012cf361%232378e78a012cf361) ---
**Author:** ![MrFloppy](https://avatars.discourse-cdn.com/v4/letter/m/43a26b/32.png) [@MrFloppy](https://boards.straightdope.com/u/MrFloppy)\ **Post date:** [March 30, 2007, 2:08pm UTC](https://boards.straightdope.com/t/legalities-of-warning-oncoming-traffic-of-radar-traps/397999/28 "2007-03-30T14:08:53Z")
[QUOTE=Q.E.D.] Day or night? If it’s day and your headlights are off, when you flash your headlights on most cars, the taillights flash too. At night, well, it’s perfectly obvious even from well behind the car doing the flashing. [/QUOTE] I don’t think that is correct. Tallights do not flash with headlights. At least here in the US. ---
**Author:** ![B.Serum](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/b.serum/32/14266_2.png) [@B.Serum](https://boards.straightdope.com/u/B.Serum)\ **Post date:** [March 30, 2007, 2:13pm UTC](https://boards.straightdope.com/t/legalities-of-warning-oncoming-traffic-of-radar-traps/397999/29 "2007-03-30T14:13:47Z")
[QUOTE=MrFloppy] I don’t think that is correct. Tallights do not flash with headlights. At least here in the US. [/QUOTE] It depends on how you “flash” your lights… I have always seen people turn them on/off, in which case all lights are affected. If “flashing” your lights means highbeam/lowbeam, then you’re correct in only the headlights are affected. ---
**Author:** ![B.Serum](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/b.serum/32/14266_2.png) [@B.Serum](https://boards.straightdope.com/u/B.Serum)\ **Post date:** [March 30, 2007, 2:46pm UTC](https://boards.straightdope.com/t/legalities-of-warning-oncoming-traffic-of-radar-traps/397999/30 "2007-03-30T14:46:32Z")
I got pulled over for flashing my lights. It was late at night and I had just driven home from college, crossing the state of Wisconsin. I was going through this small town that was notorious for it’s speed traps. I drove through very conservatively and sure enough there were two prowlers facing opposite directions, laying in wait just inside the town limits where the speed drops from 55 to 30. Yeah, they do that. Even though a driver coming in from the highway is decelerating from 55, if they’re not **at 30** by the time they hit that sign, they’re getting pounced on. _Grrrr._ So as I’m leaving the town limits, I wait til I’m well beyond the 55 sign before I accelerate. Not more than a few minutes later I see a car approaching. Well, I’m not going to let this fella get nabbed by these jerks. I flash my lights and I’m feeling good about looking out for my fellow driver. But my heart sank as I saw a **star** on his license plate as we passed one another. I promptly looked in my rear view mirror and saw the officer turn around to give chase, but I pulled over immediately, knowing damn well I had no recourse. He pulls up and asks “Are you having trouble with your lights?” “No officer.” “You weren’t trying to warn me about those officers in Fall Creek, were you?” “I dmnmumble” “License and registration, please.” And this is where it gets interesting. You see, I had already been picked up earlier that night for speeding on I-94. In cases like that, at that time, they confiscate your actual drivers’ license and give you a little pink slip that functions as your license until you make your court appearance or pay the fine or whatever. So I had to reply… “I don’t have it,” and I hand over the slip. He takes it and a bunch of things go through my mind: Is he going to confiscate this little pink slip and give me _another_ little pink slip to act as it’s substitute? Is he going to run me in right away as two infractions just a few hours apart from one another is a sure sign of a bad apple? But instead, I think he actually may have had a little empathy for the situation I was in… “You know I could ticket you right here for obstructing an officer, but I’m going to let you off with a warning.” Huh. In the end, I don’t know what laws are on what books regarding alerting other drivers of speed traps. I do think I’m obstructing the officers’ ability to charge fines, but I also think that by flashing lights, I’m actually aiding officers in their **supposed** goal of preventing people from speeding. At least, that’s the tack I would have tried if I actually had to argue my case in court. ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [March 30, 2007, 2:55pm UTC](https://boards.straightdope.com/t/legalities-of-warning-oncoming-traffic-of-radar-traps/397999/31 "2007-03-30T14:55:27Z")
When I pull back the turn signal lever to the left of my steering wheel, my headlights turn on as long as I hold the lever back, whether they were on at first or not. My taillights are not affected. It seems intentionally designed to make flashing easy. What I don’t understand…if someone flashes their headlights at me, how am I to know that means “speed trap ahead”? It’s more likely to mean, “turn down your high beam, stupid.” ---
**Author:** ![butler1850](https://avatars.discourse-cdn.com/v4/letter/b/779978/32.png) [@butler1850](https://boards.straightdope.com/u/butler1850)\ **Post date:** [March 30, 2007, 3:03pm UTC](https://boards.straightdope.com/t/legalities-of-warning-oncoming-traffic-of-radar-traps/397999/32 "2007-03-30T15:03:49Z")
Use the e-brake then. Lift it up slightly, and it’ll turn off the DRL. Put it back down, and the light comes back on. Flashes without the use of high beams, or flashing your tail lights. ---
**Author:** ![John\_DiFool](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_difool/32/19543_2.png) [@John\_DiFool](https://boards.straightdope.com/u/John_DiFool)\ **Post date:** [March 30, 2007, 3:11pm UTC](https://boards.straightdope.com/t/legalities-of-warning-oncoming-traffic-of-radar-traps/397999/33 "2007-03-30T15:11:02Z")
I also use the highbeams to let a car which just passed me know that it’s safe to merge in ahead of me. ---
**Author:** ![Voyager](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/voyager/32/133_2.png) [@Voyager](https://boards.straightdope.com/u/Voyager)\ **Post date:** [March 30, 2007, 4:49pm UTC](https://boards.straightdope.com/t/legalities-of-warning-oncoming-traffic-of-radar-traps/397999/34 "2007-03-30T16:49:38Z")
[QUOTE=SuaSponte] Your answer assumes that the driver providing the warning is aware that the approaching drivers are acting illegally, _i.e._ actually speeding. Personally, unless the approaching car is traveling at a truly excessive speed, I can’t tell whether the cars are speeding. So, usually, when I flash my high beams, I’m not aiding someone in committing an illegal act, or in avoiding apprehension for having committed an illegal act. Instead, I’m warning the approaching drivers not to commit an illegal act. That is high-minded civic virtue. 🙂 It is certainly not a conspiracy under any interpretation of penal law of which I am aware. Sua [/QUOTE] Actually, someone speeding enough so I’d notice would be the person I wouldn’t warn. 5 mph over the limit, okay, 20, not okay. I wonder if a flasher 🙂 could get off on first amendment grounds, since the flashing is a form of communications, and not the safety hazard addressed by the statutes. I wasn’t warning the driver, Your Honor, I was protesting the presence of the speed trap. ---
**Author:** ![Gfactor](https://avatars.discourse-cdn.com/v4/letter/g/9de053/32.png) [@Gfactor](https://boards.straightdope.com/u/Gfactor)\ **Post date:** [March 30, 2007, 4:52pm UTC](https://boards.straightdope.com/t/legalities-of-warning-oncoming-traffic-of-radar-traps/397999/35 "2007-03-30T16:52:17Z")
[QUOTE=Voyager] I wonder if a flasher 🙂 could get off on first amendment grounds, since the flashing is a form of communications, and not the safety hazard addressed by the statutes. I wasn’t warning the driver, Your Honor, I was protesting the presence of the speed trap. [/QUOTE] I think both of the cases I found (see links above) involved First Amendment claims. ---
**Author:** ![JeffB](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jeffb/32/188_2.png) [@JeffB](https://boards.straightdope.com/u/JeffB)\ **Post date:** [March 30, 2007, 7:30pm UTC](https://boards.straightdope.com/t/legalities-of-warning-oncoming-traffic-of-radar-traps/397999/36 "2007-03-30T19:30:50Z")
[QUOTE=DSYoungEsq] So, to sum up, if you flash the brights, you violate the law. If you flash the low-beams, you don’t violate THAT statute. Not saying there wouldn’t be others they could trot out at need. 😛 [/QUOTE] Here’s a Pennsylvania case that seems to contradict that (assuming I’m reading this right). It looks like the driver was initially convicted, and the conviction was eventually reversed: > [@](#): > > Although defendant used his high beam headlights during the middle of the day, to warn oncoming vehicles that a police car was near with a radar detector, defendant’s conviction of improper high beam use was error because the legislative intent was to prevent headlight glare during bad weather conditions or during times of darkness and defendant was cited during the day where his action had not violated 75 Pa. Cons. Stat. § 4306(A). Commonwealth v. Beachey, 556 Pa. 345, 728 A.2d 912, 1999 Pa. LEXIS 1134 (1999). > > Driver was properly convicted of improper use of multiple beam road lighting equipment after he flashed his lights from low beam to high beam approximately ten times to warn on-coming traffic of a nearby speed trap. Commonwealth v. Beachey, 698 A.2d 1325, 1997 Pa. Super. LEXIS 2193 (Pa. Super. Ct. 1997), appeal denied by 550 Pa. 686, 704 A.2d 640, 1997 Pa. LEXIS 2584 (1997), reversed by 556 Pa. 345, 728 A.2d 912, 1999 Pa. LEXIS 1134 (1999). ---
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [March 30, 2007, 7:45pm UTC](https://boards.straightdope.com/t/legalities-of-warning-oncoming-traffic-of-radar-traps/397999/37 "2007-03-30T19:45:24Z")
In 15 years of criminal and traffic practice in Ohio, including five years as a magistrate handling (among many other things) traffic cases, I’ve never heard of anyone ever actually being cited for flashing a speed-trap warning to other motorists. I’m aware of no Ohio law that would prohibit such a warning. That said, I wouldn’t be surprised to learn that some annoyed cops will warn or chew out motorists who do it. ---
**Author:** ![Jake](https://avatars.discourse-cdn.com/v4/letter/j/f475e1/32.png) [@Jake](https://boards.straightdope.com/u/Jake)\ **Post date:** [March 30, 2007, 8:04pm UTC](https://boards.straightdope.com/t/legalities-of-warning-oncoming-traffic-of-radar-traps/397999/38 "2007-03-30T20:04:34Z")
[QUOTE=John DiFool] I also use the highbeams to let a car which just passed me know that it’s safe to merge in ahead of me. [/QUOTE] Yes. Especially trucks. Even more especially tractors pulling doubles. Most of these drivers are very good but a little help, like turning off and on your lights (quickly) when there pulling back into lane in front of you, helps a lot. In bad weather it really helps! You will almost always get a running light thank you. 🙂 ---
**Author:** ![Gfactor](https://avatars.discourse-cdn.com/v4/letter/g/9de053/32.png) [@Gfactor](https://boards.straightdope.com/u/Gfactor)\ **Post date:** [March 30, 2007, 8:10pm UTC](https://boards.straightdope.com/t/legalities-of-warning-oncoming-traffic-of-radar-traps/397999/39 "2007-03-30T20:10:39Z")
[QUOTE=JeffB] Here’s a Pennsylvania case that seems to contradict that (assuming I’m reading this right). It looks like the driver was initially convicted, and the conviction was eventually reversed: [/QUOTE] Basically, the case says what the blurbs say it does. The statute, on its face, prohibits using the high beams as described above, but the Court read it together with another statute. Here’s an excerpt: > [@](#): > > Although the provision does not specify its scope of application, reason requires that it be read in connection with statutory language that sets forth the circumstances when motorists are required to use their headlights. See 1 Pa.C.S. § 1932 (statutes in pari materia are to be construed together). > > In pertinent part, 75 Pa.C.S. § 4302 provides: > > § 4302. Periods for requiring lighted lamps > > (a) General rule.–The operator of a vehicle upon a highway shall display the lighted head lamps and other lamps and illuminating devices required under this chapter [\*348] for different classes of vehicles, subject to exceptions with respect to parked vehicles, at the following times: > > (1) Between sunset and sunrise. > > (2) Any time when, due to insufficient light or unfavorable atmospheric conditions, including rain, snow, sleet, hail, fog, smoke or smog, persons and vehicles on the highway are not clearly discernible to the operator for a distance of 1,000 feet ahead. > > Thus, section 4302 sets forth the times when headlights must be used, and section 4306(a) limits the use of high beams during those times. If the two provisions were not read together, application of section 4306(a) would not be limited to the times specified in section 4302 and an absurd result would follow. Specifically, section 4306(a)'s requirement that motorists use their low beams whenever approaching another vehicle within 500 feet would be applicable during the daytime. Hence, a motorist would be in violation if, during daylight hours, he failed to turn on his low beam headlights every time a vehicle approached within 500 feet. In interpreting statutes, it is axiomatic that the legislature does not intend an absurd or unreasonable result. See 1 Pa.C.S. § 1922(1) (presumptions in ascertaining legislative intent). > > The plain legislative intent of section 4306(a) was to prevent motorists from facing excessive glare, so as to reduce the obvious safety hazard that exists when a driver suffers momentary blindness upon being subjected even very briefly to the intense brightness of high beam lamps. However, it is inconceivable that the legislature was concerned about the midday use of high beams during periods when normal atmospheric and lighting conditions make it impossible for drivers to be blinded by headlight glare. We conclude, therefore, that section 4306(a) was never intended to apply to the midday use of one’s headlights. Appellant’s conviction for the daytime use of his high beams cannot, therefore, be sustained. > > Judgment of sentence reversed. _Beachey_, 556 Pa. 345; 728 A.2d 912; 1999 Pa. LEXIS 1134 (1999). ---
**Author:** ![RedSwinglineOne](https://avatars.discourse-cdn.com/v4/letter/r/a9adbd/32.png) [@RedSwinglineOne](https://boards.straightdope.com/u/RedSwinglineOne)\ **Post date:** [March 30, 2007, 8:17pm UTC](https://boards.straightdope.com/t/legalities-of-warning-oncoming-traffic-of-radar-traps/397999/40 "2007-03-30T20:17:47Z")
> [@](#): > > 1. Nothing in this section shall limit drivers from flashing high beams at oncoming > vehicles as a warning of roadway emergencies or other dangerous or hazardous conditions ahead. “Sorry officer. I was warning oncoming drivers they were approaching a bunch of people slamming on their brakes at your speed trap.” [Previous page](https://boards.straightdope.com/t/legalities-of-warning-oncoming-traffic-of-radar-traps/397999.md?page=1) [Next page](https://boards.straightdope.com/t/legalities-of-warning-oncoming-traffic-of-radar-traps/397999.md?page=3)