This is why we need REAR fog lamps

That's awful. Would it make sense to have some kind of sensor that would automatically turn on the rear fog lamps?
 
That was near Madison, WI., just south-ish of me.
Unfortunately, I do not believe rear fog lamps would have helped very much... Maybe.... But not likely. That crash occurred just as the sun was starting to cause very bad glare, little in the way of lights would have helped unless there are shady spots due to trees or buildings, and even then, with the traffic density in that area, ..... In reality, the ONLY thing that would have prevented this magnitude of a traffic incident would be active traffic monitoring and billboard warnings (such as in Hampton Roads area and LA/SF, etc). Larger cities with high traffic control funding.
 
Oh man... I saw some videos posted on Reddit/YT a month or two ago of pile-ups in fog like this. I think it was kind of a snow-storm too, but I think if I were ever in fog like this I would immediately try to pull way off to the side of the road if possible. I've seen dash cam videos of people literally just continuing to drive full speed through fog when they can't even see 10 feet in front of their car. What the heeeeck!!!
 
Oh man... I saw some videos posted on Reddit/YT a month or two ago of pile-ups in fog like this. I think it was kind of a snow-storm too, but I think if I were ever in fog like this I would immediately try to pull way off to the side of the road if possible. I've seen dash cam videos of people literally just continuing to drive full speed through fog when they can't even see 10 feet in front of their car. What the heeeeck!!!
Yes, it's insane to try and continue at hwy speeds in these conditions. There's little to no reaction time available for anyone on the roads.
 
I have been a huge advocate of rear fog lights since I learned about them here on CF!! After our area's worst winter in 40 years last year, I bought a dedicated winter use only 4WD pickup, but can't find a bolt on aftermarket LED unit. The Peterson 850 looks like the hot setup, but I can't find one in using inferior web-fu tactics. It is hard to determine if rear fog lights would have prevented this particular event, but I believe if they were in common use, maybe the severity of this crash would behave been minimized.
 
Any kind of lights are usually not effective in very heavy fog. We have the "Tule fog" in CA and you can't see lights of other vehicles beyond about 2 or 3 car lengths at the worse conditions. At night or sometimes even in the day, you may not recognize the wall of fog you are approaching at highway speed, until you are in it. I've experienced it several times. It makes you understand how these accidents happen. At 70mph, you are traveling 102 feet per second. That's about 7 car lengths per second.

The manufacturers of newer cars have anti-collision sensors. My wife's Flex has this system. Her car just provides a flashing HUD and audible horn. Newer ones have active braking. These systems can be effective in reducing these accidents.
 
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The photometric requirements for the US and ECE rear fog light function are identical to those of the US stop (brake) light function: 80cd to 300cd on axis, with various off-axis requirements. There's a minimum lit area requirement for the stop light function that does not apply to the rear fog function.
If they are identical, why would it violate rule 11? It is certainly not illegal to do this, and brake lights are not unsafe.
Prooftexting can be a pitfall:

Whoops, looks as if I was recalling an older version of the SAE spec (J1319) for rear fog lamps. The photometric requirement is compatible but not the same for rear fogs and for stop lamps. The photometric requirements are practically identical for US and ECE rear fogs, just expressed differently due to different test voltages.

US stop (brake) light size 1, e.g., a single-compartment lamp with a filament bulb: Minimum 80cd at (H,V) and (H, 5L/5R); min 40cd at (H, 10L/10R); min 70cd at (5U/5D, V); min 30cd at (5U/5D, 10L/10R); min 10cd at (5U/5D, 20L/20R); maximum 300cd anywhere.

Rear fog light (at US test voltage): Minimum 125cd all along H line from 10° left to 10° right and all along V line from 5° up to 5° down, minimum 62.5cd within the diamond-shaped zone with corner points (H, 10L/10R) and (5U/5D, V). Maximum 250cd anywhere.

So the rear fog lamp has a slightly lower max intensity, but a higher minimum intensity at a larger range of test areas, while the stop lamp has a slightly higher max intensity, but a lower minimum enforced at more test points through a wider angular range.
The higher minima in those certain test points and other changes in the photemetry result in the fog lamp still having more apparent 'punch' to a viewer. Stop lamps aren't unsafe when used correctly, but misused stop lamps ARE.

Another aspect is if the driver is stopped with what looks like a stuck on stop lamp, they may try to explain it's a rear fog lamp, but the officer will inspect the lens markings (which aren't required, but are usually present) and find it's a stop lamp. Equipment malfunction. With the correct lens markings, you might not escape being stopped but it should resolve itself much more readily.

Virgil does not advocate using this set up but explains how to do so if one must.
But when is "if one must"?

Maybe: You've got everything set up for your rear fog lamp except for the lamp itself. You've got somewhere to be in another state, but in the next county and along the way to your destination, you know the Schlep Boys (Jammy, Joe, and Mack) have the 850F. However, there's a heavy fog forecast. You want to have a stopgap measure, so you dig out one of your spare Peterson 850R stop/tail lamp modules and install it. You get to the Schlep Boys safely, and install the 850F.

But if you're planning this installation and have neither a spare 850R nor an 850F, just order the 850F and build it right the very first time.
 
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what a wrong statement!
:(
rear fog lites would not have helped ANYTHING there (or at any other occasion else).
The only thing they do is that some idiots turn them on - mostly in situations where they are used wrongly, like in rain - and forget about them afterwards.
I admit ONE SITUATION: when You are last and somewhere on the country.
But in typical traffic they are totally idiotic, blinding anyone behind.

The PROBLEM are drivers that
* drive too quick for the situation
* leave no distance
* and so on, insert most any error to think of

but I must admit, the idiots keep getting less. Nowadays there are only 2-3 left on my 40 km to work in the morning that insist on using their rear fogs at the nicest winter days.

PS: Jaycee's idea is great!
but it has to be finalized:
a sensor that turns that totally unnecessary rear light OFF, when no longer needed
or even better and cheaper: a "pushbutton setup" for turnig it on (no steady mechanical "switch") that kills the light, when the ignition is turned off
 
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what a wrong statement!
Whoaaaaa, dogie! What an inflammatory statement.

You realize Austria, being a UNECE signatory, requires rear fog lamps on all roadgoing vehicles. And why do they, along with the other UNECE signatories? It may well be that they are proven to reduce rear-end collisions when used appropriately.

Could/should the function be fully automated? A nice idea, but then what about the driver using a car not so-equipped? We can't just let the technology do everything-- drivers do need education and training for the other features to truly be effective. We see drivers going without headlamps because their DRLs are on and their dashboard is all lit up, and instead of red warning that "lights are required but not on", instead we have a green indicator showing that they ARE on when on. I think a present red warning is more effective than a not-present green indicator. Ultimately, it is the operator of the vehicle who is responsible for the operation of the vehicle, and so they do need to know more about what the functions are and how to use them appropriately.

Similarly, new cars having forward-collision detection systems are a great idea, but perhaps our rear turn signals should have been separate and amber this whole time, which is much more effective as a warning to other drivers and is helpful to people with or without those systems.

And, finally, there are already some stringent wiring and "telltale" requirements:

UNECE R48 said:
6.11.7. Electrical connections
These shall be such that:
6.11.7.1. The rear fog-lamp(s) cannot be switched on unless the main beams, dipped-beams or front fog-lamps are lit;
6.11.7.2. The rear fog-lamp(s) can be switched off independently of any other lamp;
6.11.7.3. Either of the following applies:
6.11.7.3.1. The rear fog lamp(s) may continue to operate until the position lamps are switched off, and the rear fog lamp(s) shall then remain off until deliberately switched on again;
6.11.7.3.2. A warning, at least audible, additional to the mandatory tell-tale (paragraph 6.11.8.) shall be given if the ignition is switched off or the ignition key is withdrawn and the driver's door is opened, whether the lamps in (paragraph 6.11.7.1.) are on or off, whilst the rear fog lamp switch is in the "on" position.
6.11.7.4. Except as provided in paragraphs 6.11.7.1., 6.11.7.3. and 6.11.7.5., the operation of the rear fog lamp(s) shall not be affected by switching on or off any other lamps.
6.11.7.5. The rear fog lamp(s) of a drawing motor vehicle may be automatically switched off while a trailer is connected and the rear fog lamp(s) of the trailer is (are) activated.

6.11.8. Tell-tale
Circuit-closed tell-tale mandatory. An independent non-flashing warning light.

It's clear that in some areas, drivers aren't well equipped to handle such a hazardous road condition. The drivers of lead vehicles have to make some touch choices, like do I keep going? Do I slow down? How much do I slow down? The rear fog lamp helps give the drivers behind them additional warning that they, too, should be slowing down.

One thing that could help mitigate all this is better vehicle-to-vehicle, vehicle-to-infrastructure, and infrastructure-to-vehicle communication (V2V, V2I, I2V, read about some of it here)-- again, technologies that might begin to be available in future model years but not in every car.
 
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what a wrong statement!

Well, no.

rear fog lites would not have helped ANYTHING there (or at any other occasion else)

Now that's a wrong statement. For one thing, nobody has an alternative-universe crystal ball to tell for sure what would have happened in this case if one thing had been different (vehicles equipped with rear fog lamps). That said, rear fog lamps are known to reduce crashes, and have been since the early 1960s.

The only thing they do is that some idiots turn them on - mostly in situations where they are used wrongly, like in rain - and forget about them afterwards.

You're objecting to some drivers' misuse of rear fog lamps. That's a legitimate objection -- people should use their car's equipment correctly -- but it doesn't mean rear fog lamps are useless. By your logic, turn signals are useless because some people fail to use them, or leave them on after completing a turn or lane change. That doesn't make any sense, and neither does what you say.

The PROBLEM are drivers that
* drive too quick for the situation
* leave no distance
* and so on, insert most any error to think of

Right, and rear fog lamps aren't a magical countervail to make drivers behave better, but they do afford a longer visibility distance in bad weather. That's how they provide a safety benefit.

or even better: a "pushbutton setup" for turnig it on (no steady mechanical "switch") that kills the light, when the ignition is turned off

This requirement is already built into UN Regulation 48, which states:

6.11.7. Electrical connections
These shall be such that:

6.11.7.1. The rear fog-lamp(s) cannot be switched on unless the main beams, dipped-beams or front fog-lamps are lit;

6.11.7.2. The rear fog-lamp(s) can be switched off independently of any other lamp;

6.11.7.3. Either of the following applies:

6.11.7.3.1. The rear fog lamp(s) may continue to operate until the position lamps are switched off, and the rear fog lamp(s) shall then remain off until deliberately switched on again;

6.11.7.3.2. A warning, at least audible, additional to the mandatory tell-tale (paragraph 6.11.8.) shall be given if the ignition is switched off or the ignition key is withdrawn and the driver's door is opened, whether the lamps in (paragraph 6.11.7.1.) are on or off, whilst the rear fog lamp switch is in the "on" position.

(boldface type added for emphasis)

This requirement is at least 8 years old now, and probably helps explain why, in your words, "the idiots keep getting less. Nowadays there are only 2-3 left on my 40 km to work in the morning that insist on using their rear fogs at the nicest winter days".
 
I've wondered any number of times if those devices that put a "warning don't get too close line" behind your car with a laser would be a good thing to make standard on vehicles.
 
I've wondered any number of times if those devices that put a "warning don't get too close line" behind your car with a laser would be a good thing to make standard on vehicles.

Wonder no more! Those are eBay toys, and variations in the road surface make that line jagged and full of gaps at best. At worst, they can (through specular glare) be searing to another driver's eyes. Remember, angle of incidence equals angle of reflection.
 
This is a bit off topic but I see the word "idiot" thrown around a lot on this forum when talking about misuse of different types of equipment in vehicles such as foglights. In some cases people are idiots but in many cases they just simply aren't taught. I think that proper use of lights, proper speeds to drive in different conditions and amongst many other things should be on the drivers test when getting your drivers license and that as any traffic laws change or as new vehicle technologies are implemented into vehicles there should be a mandatory refresh on these things at the time of ones drivers license renewal. A lot of ignorance that people display on the road should be blamed on the government I think,and are not simply people being idiots. The government has a responsibility to inform it's citizens and not leave it up to them to "just figure it out".

Hope that is legible. Typed it on my phone.
 
I admit ONE SITUATION: when You are last and somewhere on the country.
But in typical traffic they are totally idiotic, blinding anyone behind.

I couldn't agree more.

When in a line of vehicles (you're only driving as fast as the slowest car anyway),only the front and rear car should have fog lights on, unless in fog where you can't see five feet in front of you (extremely rare). I believe that's written into the driving rules here in Slovakia, but it may just be a recommendation.

Driving behind someone with the rear fog light on (at eye level yet) in less dense fog is like someone having their brake lights on constantly in front of you. Much more annoying than those red turn signals in another thread and probably just as dangerous.
 
When in a line of vehicles (you're only driving as fast as the slowest car anyway),only the front and rear car should have fog lights on, unless in fog where you can't see five feet in front of you (extremely rare). I believe that's written into the driving rules here in Slovakia, but it may just be a recommendation.
[Citation Needed]

Driving behind someone with the rear fog light on (at eye level yet) in less dense fog is like someone having their brake lights on constantly in front of you. Much more annoying than those red turn signals in another thread and probably just as dangerous.
Have you tried not following too closely? As far as "eye level", there is some amount of latitude for mounting heights:

In height: not less than 250 mm nor more than 1,000 mm above the ground. For rear fog lamps grouped with any rear lamp or for category N3G (off-road) vehicles, the maximum height may be increased to 1,200 mm.
But usually they're closer to the 250mm height than as high up as 1 or 1.2m.
 
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For those of us who drive vehicles that don't have rear fog lamps, what would be the next best way to improve our visibility to the motorist behind us? Turn on the hazards? Or would that be too confusing?
 
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