Rear fog light(s)

What's a standard brake light cd? I would think you would want the rear fog to be brighter correct? I am thinking of installing one and I like the BD S2. I have no issues cutting a hole in my rear plastic bumper and installing this. Although the BD doesn't look like it would be easy to install this way.

 

You mean the drivers behind you also driving in the fog need to be alerted to the presence of fog????

Wouldn't the other drivers already know they are driving in fog?

 

Maybe you should have gotten the context for what you quoted. It was an answer to a direct question from colton.

 

NHTSA Interpretation 9418 has some interesting information that may be useful as well as reference documents. I copypasta'd the relevant parts of the opinion below. TL;DR - it is the manufacturer's responsibility to ensure that rear fog lights do not impair the effectiveness of other lighting systems on the vehicle and there are no federal requirements (including S 5.1.3 of Standard 108) for rear fog lamps so the NHTSA refers the letter's author to the AAMVA.

The back and forth in this thread led me to a bit of digging and, unfortunately, all I can find is the NHTSA weighing in on manufacturer's standards. In my opinion, my non-legal non-lawyer opinion... if you follow the advice in Interpretation 9418 and install rear fog lights on your rig that do not impair the effectiveness of other lighting systems (a reasonable person would be able to distinguish when you hit the brakes and use the turn indicators) I think you are safe, but make your own call. I have not been able to find a definitive "Yes [or no] rear fog's are legal." If any of you find some documentation stating otherwise, please include it in this thread.

Keep in mind the context and language here. The NHTSA says "as original equipment," we are all on TW as owners so we will never install anything on our rigs as original equipment.

References:

• Code of Federal Regulations, Title 49 - Transportation, Standard Number 108
• NHTSA Interpretation 9418
• SAE J1319_201510 *Paywalled and ONLY a recommendation NOT LAW!

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Questions submitted are in quotes + bold w/ answers in reg text. Full interpretation linked above.

"Is the rear fog lamp in a combined rear lamp unit permissible in all the states of the U.S.? There is no statement in the FMVSS 108."

Paragraph S5.1.3. of Standard No. 108 prohibits the installation as original equipment of additional lamps such as rear fog lamps if the additional lamp "impairs the effectiveness of lighting equipment required by the standard." The determination of whether a rear fog lamp in a combined rear lamp unit impairs the effectiveness of other lighting equipment is initially that of the manufacturer of the vehicle on which the lamp is installed. Unless such a determination is clearly erroneous, this agency will not question it.

We do not know whether a rear fog lamp in a combined rear lamp unit is permissible in all the States. Because a fog lamp is not required motor vehicle equipment under Federal law, each State in which it is used may regulate it according to its own laws. We are unable to advise you on the laws of the individual States, and suggest that you ask the American Association of Motor Vehicle Administrators (AAMVA) for an opinion. Its FAX number is 001 703 522 1553, and its address is 4600 Wilson Boulevard, Arlington, Virginia 22203.

"Which photometric requirements do we have to fulfill for the rear fog lamp?"

There are no Federal requirements that apply to rear fog lamps, and, as noted above, we are not conversant with state requirements. For your information, the latest specification of the Society of Automotive Engineers for this item of equipment is SAE Recommended Practice J1319 AUG87 "Fog Tail Lamp (Rear Fog Light) Systems."

"Is the certification of the combined rear lamp unit binding upon the whole states of the U.S.?"

No. The certification of the vehicle manufacturer is its representation that the vehicle complies with all applicable Federal motor vehicle safety standards, including paragraph S5.1.3 of Standard No. 108. A State has no authority to question this certification.

 

Yes, I read and understand the answer.

What I don't understand is WHY the drivers behind you need to be alerted to fog. Wouldn't they already be driving in the fog? They should be aware they are driving in fog. So what is the purpose???

Maybe there should be a light to tell the driver behind you they are driving.........

 

Google is your friend, friend. Allow me to cut and paste...

Frontal fog lights are designed to help you see the ground better in low visibility circumstances. Similarly, rear fog lights (or rear fog lamps) are there to help other drivers behind you avoid hitting you. Rear fog lights help with interpreting distance and serve as an extra set of low-level lights for other drivers to see. Source

 

I can't tell I'd you're asking a serious question or just trying to be argumentative. Have you never driven through fog, snow or rain so thick you can barely see the end of your hood? A rear fog light is to help the person behind you in those conditions see you before they rear-end you.

 

Isn't that the purpose of TAIL LIGHTS?????

Seems redumbant and unnecessary.

But hey......if you "feel" the need. Then by all means. I'm just trying to understand how this is an aide.

 

Don't be daft. No, I'm not trying to be argumentative. As I said, I'm trying to understand the advantage beyond having tail lights.

I live in Iowa. You would not believe the conditions I've driven in.

The absolute most butt puckering situation was a WHITE-OUT during a blizzard. Nothing visible past the windshield wipers........ drove by feel.

 

It is the brightness a brake light so it is WAY more noticeable. If you think it is unnecessary just move along.

 

Sorry......Please pardon me for trying to understand the advantage behind these items.

sure.....I can move along.....

Happy New Year. Drive Safe and be sure to use those rear fogs tonight.

 

I'll respond to you one more time in good faith, as I don't think you are here to troll. Running lights are fine in typical driving conditions but fog limits the distance light can travel. This is where the rear fog light comes in, it's purpose is to be brighter so that drivers that may be driving the same direction and approaching at greater speeds can identify you at a safer distance. Fog can occur in icy or snowy or rainy conditions which will increase the distance to stop. The fog lights are to alert drivers behind you that do not see your running lights at a distance (because... you know... THE FOG) that you are there.

Example below. Compare the running lights to the fog light in twilight. Night time and thicker fog would only obscure the running lights more. In a pitch black situation with heavy fog the car behind the bimmer would be able to see the red light at a greater distance. I'm not sure how to explain this better so you will understand. Hopefully this does it. I encourage you to drive a windy mountain road in heavy fog conditions at night with a friend in front of you to test how well those tail lights do.

 

Great photo illustration, thank you for that.

 

I have decided after talking to Daniel stern, the boys at the candlepower forum and reading the regs that I'm not going to try making a "red" light work. Going to order a real Hella rear fog light.

 

Like this?

Hella 91163125129, 003030151 Fog Light; Rear SKU: 1262416-HL-91163125129 - Porsche (autohausaz.com)

 

No, this one. Should be pretty invisible under the bumper until turned on.

https://catalog.hella.com/catalog/product/view/id/109417/s/2NE 980 889-501/

 

Just ordered the above linked hella for $57 off of amazon.de

 

found this site that seems to be a one stop shop for rear fog light components, some interesting lights that have me reconsidering the Hella choice.
https://www.carbuilder.com/us/search?q=rear+fog

These 2 items seem particularly interesting.
https://www.carbuilder.com/us/rear-fog-light-controller-for-new-iva-rules-for-momentary-switch


https://www.carbuilder.com/us/natural-billet-aluminium-rear-fog-switch

 

Virgil, one of the moderators on the candlepower forum and involved in all of the rear fog light threads pointed out this kit for wiring...
https://cartown.se/index.php?route=product/product&product_id=307