Rear Fog Lights for Driving in the USA? What ARE They?

Please note:  All photographs here and in other articles on this website are taken from the passenger seat and with telephoto lenses, from much further away than the resulting images appear to show.  Safety is never compromised to get a photo.

Sadly, in the USA, matched pairs of high-intensity rear fog lights are not permitted. Indeed, if I ask American drivers about this – which I frequently do – they haven’t even got a clue what rear fog lights are.  So let’s get the answer out of the way:  Rear fog lights are red, they are very bright and they must only be used (to protect your ‘six’) in bad visibility.

The car near the center of this photo, which has a matched pair of rear, high-intensity fog lights illuminated — not brake lights — will clearly remain more visible than even cars nearer the camera that have only their regular rear lights to rely upon. Look at the two cars just beyond and to the left of the well-lit car: both of them do have their regular tail lights on yet are fading from view. The difference in safety is very obvious.  Copyright image.

To say that the absence of paired rear fog lights is a pity is an understatement because these things save lives. Admittedly, cars from Europe can be imported to the USA with just one rear fog light fitted – not the two they have when on European roads – but as I will show below, this is inadequate and less safe.

Here, a car in heavy spray and with just one rear fog light makes it obvious that in worse visibility or at a greater distance away, only the one light will remain visible. In those circumstances, it is much harder for a driver following your vehicle to correctly assess how big the gap is, between the vehicles, and that  makes the situation significantly less safe. (Had you spotted the tall truck, visible between the two cars the camera vehicle is following? )  Copyright image.

About 15 years ago, at an event in Manhattan, I asked some top-level, European vehicle engineers about this silly situation and was told that paired rear fog lights are not permitted in America “in case people mistake them for brake lights!” This reason would be hilarious if it weren’t so stupid.  Pairs of these very bright, additional rear red lights have been used in Europe for 3-4 decades, and not once – not even when I was a traffic patrol police officer investigating crashes – have people ever even implied to me that they confused rear fog lights with brake lights.  Once informed, even a child would instantly know the difference between them.

Let’s imagine a scenario: You are driving your sedan or SUV  in the half-light of dawn or dusk in very thick fog but its 20 miles to the next exit so you have no choice but to continue, by driving as slowly as the conditions dictate.  (Stopping on the shoulder in bad visibility can be even more dangerous than continuing, unless you were to cross right over the shoulder and drive on the grass, as far away from the asphalt as possible.)  Coming up behind you, driving too fast for the conditions, let’s say there is a fully loaded 18-wheeler semi-tractor-trailer; the driver is late and he’s in a hurry.  What happens next?  Do you want him to say “Those lights ahead are very bright.  I wonder whether they’re brake lights!<<joke>>  Or instead, do you want him to wonder what he has just rammed from behind because he didn’t see anything until it was too late and he slammed into your car and wrecked it… and perhaps you and your family!

The whole purpose of having rear fog lights (plural) is so that not only can other drivers see your vehicle from behind, from a much greater distance in fog, heavily-falling snow, thick smoke, heavy road spray or even sandstorms, but also – when there are two of the lights and not just one – they permit drivers behind you to gauge the distance between their vehicle and yours quite accurately. A single bright rear light often does not allow the same degree of awareness.

Once again, the more distant car, with its rear fog lights in use, is very obviously the most conspicuous. Copyright image.
A close-up of the distant vehicles in the photo above. Had you spotted the third car? Its near-invisibility could be lethal. Copyright image.

There is an answer to concerns about such bright lights being inappropriately used when there is good visibility and the lights’ brightness becomes a nuisance. It is, of course, called the law – specifically one that prohibits the use of rear fog lights unless atmospheric visibility (as opposed to just night-time darkness) is bad.  A similar law should already be in existence to prevent people having their front fog lights on except in the conditions described, but in most if not all states, no such law yet exists.  The very low mounting height of front fog lights means they create a serious amount of glare on clear nights, even though they don’t actually dazzle, yet in those conditions they serve no good purpose whatsoever.  That, however, is the subject for another article which will be linked here in due course.

So there you have it. High-intensity rear red fog lights have been around for at least one third of a century.  They are used in quite possibly all of the countries that have a much better road safety record than the USA.  Yet still, somebody in some little office took it upon him/herself to decree “not in America!”  That person or committee’s ill-informed decision has very likely cost a lot of Americans their lives or their limbs in thousands of bad-visibility crashes over the years.

How about it, NHTSA?  It is time for a re-think (preferably by reference to overseas best practices).  It would be so easy to use this inexpensive, additional equipment to make bad weather driving significantly safer.

Oh, and please don’t let Detroit force its penny-pinching refusals on you over topics like this. Contrary to their apparent belief, their profits are emphatically not more important than the lives of the people of this great nation.

Eddie Wren, CEO & Chief InstructorAdvanced Drivers of North America

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Author: EddieWren

Eddie Wren is the CEO and Chief Instructor at Advanced Drivers of North America. His driver safety background is given at: http://www.advanceddrivers.com/ceochief-instructors-resumecvbio/

17 thoughts on “Rear Fog Lights for Driving in the USA? What ARE They?”

  1. It should not be illegal to use front fog lamps when visibility is not reduced. The glare you are talking about must be a European thing as there are pretty much no roads that are smooth enough that glare or reflection could happen. I use them as additional light to my headlights that aren’t very bright. They in no way have a negative effect on other drivers on the road and allow me to see better, even well enough to avoid some deer on the highway.
    As much as it sounds stupid, many drivers would take the rear fog lamp to be a break light. People can’t even figure out how to use round-a-bouts and flashing yellow arrows correctly.

    1. Hi, Alicia, and thanks for taking the time to post a reply.

      Regarding rear fog lights, what you are voicing is merely unfamiliarity with them, and who can blame you for that. None-the-less, I can guarantee you that nobody mistakes them for brake lights, for several reasons:
      1. It is easy to tell whether a vehicle is actually slowing down or not, so there’s a 99% certainty that if it’s not slowing down, the lights are rear fogs and not the brakes.
      2. Rear fog lights are actually housed in a different, additional section of the lighting cluster, which isn’t hard to see and which still allows following drivers to see when the brake lights really do come on.
      3. Rear fogs really are very bright in order to do the important safety job they are designed for. So if someone has them on when they are not needed, everyone around will know by the brightness exactly what they are.

      And the point still remains: Do we want our vehicles and therefore ourselves to be better protected in bad weather conditions? If so, these things are worth their weight in gold.

      Now, on the subject of keeping your front fog lights on, I’m afraid you are simply repeating a fallacy regarding the deer scenario. This is all down to the laws of physics. By their design, fog lights do exactly what you say; they light up areas to the sides of your vehicle, and this is to help you be able to see the edge of the road and/or lane lines when the visibility is bad. However, they also don’t shine very far ahead of the vehicle at all – perhaps just 20-30 feet ahead in terms of useful illumination.

      When you are driving along at – say – 30mph, your car is moving at 44 feet-per-second, so assuming the frontal, useful spread of your fog light beam is 30 feet you will cover the range of your fog lights in just 2/3rds of a second. But this is where the common myth about deer, etc., is blown out of the water. The average driver’s typical reaction time – despite people so often boasting about what good reactions they have – is typically 1.3 to 1.5 seconds. This means that while you might indeed glimpse a deer on the grass verge and heading into your path, in reality you almost certainly won’t even get your foot to the brake pedal, let alone do any significant braking before you hit the animal. Unless your car is, say, on a left-hand curve and it was, in fact, your headlights that showed you the deer, further ahead, it is typically humanly impossible to react in time to miss a deer that is only 30 feet ahead even at just 30mph, and of course if a car is travelling faster than 30mph the math becomes really silly.

      I’m not criticizing you – many people feel exactly the same as you do – but it is a misconception and frankly a “security blanket” that doesn’t do any good whatsoever.

      As for whether or not keeping fog lights lit on a clear night causes additional glare (which is different to “dazzle”) one only needs to look at cars or SUVs coming towards you that have fog lights switched on and those that do not. The difference is significant. And what glare does is make it harder for an oncoming driver to see beyond the car that’s causing the glare – a very undesirable situation. Indeed, the problem is so well recognised that in many (and probably all) European countries, a driver using front fog lights in clear conditions will get a hefty ticket for their forgetfulness and/or lack of consideration to others.

      Finally, I guarantee that there is no significant difference in the road surfaces that would change the level of the glare.

      I’m sorry this is such a long answer but clearly I have to explain these points for everyone who reads this post. Thanks again for your comment.

      1. No problem on the longly worded answer. I agree that you can tell which oncoming vehicles have fog lamps on. But I have never had an issue with them being on since, as you have stated, they shine closer to the vehicle. My issue is with the super bright headlights. I have often found myself cursing someone for having their brights on only to see when the vehicle is closer that it is just super bright headlights. I do not put my fog lamps on just for the deer scenario, but it has been just enough side light to illuminate deer eyes in the fields. Though fog lamps do illuminate closer in, there is some overlap with the lights the headlights put out. That additional light is what I use them for.

        1. I agree, Alicia — some of what you quite accurately call “super bright headlights” really are uncomfortably bright, but then that is dazzle, as opposed to glare — two different problems. 🙂

    2. Goodaye Alicia, sorry, you must have also been dazzled by drivers thinking they are “cool” driving with their very bright fog lights on. I am an Australian truckie and I wish they were not used at all here. People seem to think they replace daytime running lights and in rain, they actually cause more glare than giving vision, and I have nearly collected a person on the side of the road in rain, due to the glare of badly aligned “fog lights”. It is illegal to use them in other than fog or “inclement weather” and as far as I and many truckies are concerned, it should be policed much more. You would too if you had to be blinded by them 100’s of times each night. We do not have a law requiring a dash warning light for forward facing foglights and this might help with those who forget, but overall, I firmly believe they cause more trouble than they solve. Cheers Rod.

  2. From: JSTR [mailto:gladiator15@mchsi.com]
    Sent: Thursday, June 22, 2017 10:29 PM
    To: e.wren@advanceddrivers.com
    Subject: Rear fog lights

    I was stationed in Europe and at that time only one rear fog light was legal. Additionally, it had to be placed so it would not be confused with the rear break lights. I left Germany in ’78 so perhaps the law has changed.

    Rear fog lights work. I had one installed on my ’71 914 Porsche by the Porsche dealer when I stationed in Germany. I now have a 2015 Toyota Tacoma and I’d like to install one on it and hook it up as an independent light, not associated with the front fog lights. I just had some real harrowing experiences today, and about two weeks ago. I drove up to Connecticut to visit family. I live in Dover, Tennessee and when I left, it was raining to beat the band and got worse. I took, I-24 to I-40 and then on to I-81. Well, it takes me six hours of driving in Tennessee before I leave the state. For those six hours, it was 70 mph all the way and the visibility was about a vehicle length and a half. Couldn’t see the 18 wheelers beyond that. Just a vague grey shape in the mist and rain. You either drove at the speed of traffic or got off of the road. No in between. It would have been nice to have a rear fog light for my own sake. Nothing like getting run over from behind. Coming back was uneventful, until I hit Tennessee, just past Bristol and it started all over again. Another six hours of hair raising driving. And what made things worse, there were people driving without their lights. White vehicles were impossible to see. Also light colored ones, (silver) (silver grey) and such. Even the 18 wheelers with their glass marble type tail lights were hard to see and they are a great improvement over the plastic lens lights of yesteryear.

    Just thought I pass that experience along. I’m familiar with those rear fog lights and they really do work. I wish they would be standard equipment

    Thanks for your time,

    Ron Pauluh

    1. Thanks, Ron. It’s great to encounter anyone from North America who has experience of rear fog lights and knows their great value in increased safety!

  3. Goodaye Eddie, I did reply to Alicia and have seen rear fog lights on in rain that bright, that I could not see the brake lights activate. Please read my reply to Alicia. We require under law a dash lamp for rear fog lights on, but not forward and driving all night on our less than perfect roads, badly aligned fog lights, those who put bigger bulbs in and even worse, those with caravans and or the back of the car loaded down, then have their fog lights in your eyes all night, let alone the problem with them on wet roads. Cheers Rod.

    1. Hi, Rod; it’s nice to have an Aussie ‘on board!’ I’ve read your earlier message to Alicia, as you requested. I agree with you entirely about the strong need for warning lights on the dash in respect of both front and rear fog lights — both are compulsory in Britain. Similarly in Britain, it is illegal to use either front or rear fog lights unless visibility is sufficiently bad to meet certain very strict criteria. You have already pointed out how big the problem can be when people keep front fog lights illuminated at night when there is NOT bad visibility, and as a former UK traffic patrol police officer (now living in the USA), I do know that you are not exaggerating in any way. We used to enforce the ‘no front fog lights’ law very strictly, and I also agree with you about the need for that enforcement. Cheers mate; Eddie.

  4. Hi Eddie, Good work on updating the website, this must be a lot of work.
    On the subject of US ‘mis’-use of fog lights. I regularly drive a section of road in Santa Barbara county that has a left turning bend, also at the brow of a hill. If the oncoming vehicles have fog lights on, it is a virtual guarantee of blinding or dazzling the drivers on my side of the road. Since I know this section of road, I now make a point of avoiding it at night if possible.
    On a technology note, it is hypothetically possible to disable the front fog lights above a certain speed. As you pointed out in an earlier comment they do not serve any purpose other than vision of the road immediately in front, and thus cannot improve ‘actionable’ visibility at speeds much over 30 mph. If the vehicle manufacturers programmed the lighting controls to automatically switch them off, or gradually reduced the brightness as vehicle speed increases, this would reduce the instances of dazzle or ‘blinding’.

    1. My apologies, John. I don’t like failing to reply to a comment, and as always you have made some valid points. Forgive my tardiness on this occasion. Your comments are always welcome.

  5. Although this article is a few months old now I felt I should reply having read it. As a Brit living in the US I have never understood why we do not have rear fog lamps at all – especially when you read almost every year, about massive pile ups on highways due to fog/snow etc.

    The biggest problem I had with driving here was indeed the indicators on a lot of cars being red and not orange. Someone commented that drivers may get the rear fogs mistaken for brake lights, but I had issues until accustomed to not really noticing a signal before it just looked like a brake light when on!

    Safety should always be far more important and it is such a simple thing to accomplish – after all we all have the high brake lights that we never used to have.

    With lights in general though I do not think people know how to use them – I’ve had high beams in my face, front fogs on a clear day that reflect off a damp road and my pet peeve is day time running lights – they should be BANNED!!!! Numerous times I’ve seen drivers on normal roads or freeways without their lights on because with day time running lights you get front lights and your dash lights so easy to forget but you do not have rear lights so you are invisible until another car is close enough!!!

    1. Matthew, thanks for your reply and accurate comments.

      You are entirely correct about the disadvantages of having red rear indicator lights, rather than orange. It creates a less conspicuous warning and is particularly bad at dusk and dawn, in heavy traffic and either fog or heavy rain/spray, and it is already on my list of additional blog topics.

      Similarly, the use of front fog lights in clear conditions is another issue I have yet to address… I have over 60 topics awaiting my attention on the aforementioned list! 🙂

  6. Hi everybody,

    I’m european, I live in the US, and I’m puzzled about a few comments I’m reading here. I’ve been driving cars in several countries with different regulations, and here are my two pences about the issue:

    1. Front fog lights very rarely dazzle. I find it stupid to use them when you don’t need them, but it’s usually a danger. What *really* blinds you are the high beams, and in this country there are many drivers that don’t switch them off when they see drivers in front. After living here for two years, I can say that the front fog lights are not an issue, but the misuse of the high beams is.

    2. In all my years of driving in Europe under terrible fog conditions and hard rain I’ve never mistaken a rear fog light for a braking light. In any case it-doesn’t-matter. Really. In Europe you are allowed to use the rear fog light only under very bad conditions, otherwise you can get a citation. And under those very bad conditions everyone drivers slowly, because many times you can’t even see the road. It’s so great to have a rear fog light in front of you so you know where the road is!!!

    3. Red rear indicators can be an issue. In Europe the police will stop you if one of your lights is not working properly, very few drivers risk to go out without working lights because of this. Here it seems that the rules are much more relaxed, and when you see one blinking rear light many times I’m not sure if there is a guy with a broken light that is braking or someone that is turning. In general this can be quite confusing. The only argument in favor of the red rear indicators is that “they look cooler”, but really, c’mon.

    Hope it was useful to have a point of view from the other side of the ocean.

    1. Alex, thanks for your comment.

      We are entirely in agreement with your second and third points but would like to clear up something on your first point: We are not accusing front fog lights of ‘dazzling’ other drivers, although they can get uncomfortable if the road is very wet and therefore more reflective. They do, however, increase glare — or think of it as ‘light polution’ if you wish. Put simply, the more white lights there are coming towards you, the more difficult it is for an opposing driver to see anything at all beyond them, which of course is not a desirable effect. You mention that in Europe drivers are only allowed to use rear fog lights only in very bad conditions or the police will deal with the matter. Well, for the reasons I mention above it is entirely possible to get booked (or ‘cited’) in Britain for using front fog lights other than in conditions of fog or falling snow and given the generally harmonious nature of European traffic laws, I suspect that applies throughout the rest of Europe, too.

      Incidentally, the reason that American cars have red rear indicators is undoubtedly because it saves money — albeit probably a fraction of one cent per car — and sadly U.S. automakers have frankly always put profit ahead of maximum safety, only pursuing the latter when obligated to do so by the Government, in the form of the USDOT and NHTSA.

      I hope that helps.

  7. I take issue with some opinions re: fog lights in the U. S. Regulations stipulate that rear running and brake lights must be red; amber/yellow are permissible only for turn indicators. Rear red should be no different in visibility from Euro red fog lights, and mistaking such for brake lights may be a good thing, logically telling a driver to slow and/or brake to keep a from overrunning the vehicle ahead. Properly designed and aligned front fog lamps can be white or yellow/amber, but set up as low as possible on the front, pointing slightly down, but with a strong cutoff above horizontal to minimize both direct beam aim into oncoming drivers eyes, but also to keep the glare from diffusing into the fog above, in the same manner as high beams do compared to lower directed and properly aimed low beams. Newer studies have rediscovered perhaps lost wisdom regarding eye strain from blue-white lighting compared to yellower old tungsten sealed beams, and most potentially problematic, lo and behold, blue-white light flushes our adaptive night vision pigmentation which can take several minutes to restore (red instrument lights and LEDs do not). Essentially, on roads with lots of traffic at night, we are constantly driving in a night-blind state. I further notice that because heavy fog, rain, or snow make the scene a monochromatic cold white and grey, any yellow or red light really stands out. Although I have not seen spectrometer readings of modern headlight beams, tungsten and halogen by definition produce full spectrum coverage, but LEDs may lack nearly all red or R9 in CRI jargon used to spec home and business lighting. At night, in fog or snow even in daytime, red will shift to very dark, even black, and without reflective markings, pedestrians disappear in such settings, made worse by the mistaken notion that blue-white headlights are “brighter,” while the truth is the brightness is mostly in the blue wavelength which does not provide any overall benefit in the yellow to red wavelengths we respond to in normal daylight levels, and which help us identify what is ahead on the road and shoulders. I have driven hundreds of miles at night, where too many times the black void of the highway is only framed by whatever reflective markers and signs happen to be on either side. In balance, this does not seem to be an improvement over older headlight technologies.

    1. Indeed. In some countries there are helpful laws which prohibit the use of front or rear fog lights in conditions other than fog or falling snow. If correctly enforced, this prevents reflected glare from front fog lights and dazzle (albeit red) from rear fog lights.

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