[dbs600]

I know coding can resolve this and that high beams aren’t meant for fog, but anyone know why fog lamps don’t remain on with high beams?

Fog lamps provide additional lighting that should remain on if maximum lighting is desired, no?

[BMWrules7]

Originally Posted by dbs600

I know coding can resolve this and that high beams aren’t meant for fog, but anyone know why fog lamps don’t remain on with high beams?

Fog lamps provide additional lighting that should remain on if maximum lighting is desired, no?

In the USA, federal guidelines require fogs shut off when hi beams selected.

1. The prevents over bright conditions that could dazzle oncoming traffic with an amount of light normally reserved for emergency vehicles. (My poor speculation)
2. In many cases with fog present, it is best to turn off the high beams to prevent reflection from obscuring your view. (Maybe the Feds don't want you to make the mistake of using hi beams when it's foggy outside.)

[dbs600]

Originally Posted by BMWrules7

In the USA, federal guidelines require fogs shut off when hi beams selected.

1. The prevents over bright conditions that could dazzle oncoming traffic with an amount of light normally reserved for emergency vehicles. (My poor speculation)
2. In many cases with fog present, it is best to turn off the high beams to prevent reflection from obscuring your view. (Maybe the Feds don't want you to make the mistake of using hi beams when it's foggy outside.)

Thanks for the great info, BMWrules7!

So it's due to a restriction limiting forward lighting for safety!

[493263]

Because fog lamps and high beams have very close angles. In other words, it doesn't dip down at a steeper angle than low beam. You don't need to have them both on at the same time.

That's why you're not supposed to use fog lamps in normal driving condition because fog lamps can still blind people from far away in the opposite lane. The only reasons why it's not as distracting as high beam is because it's generally a weaker output bulb and it's placed very low to the road.

There's a few people in this forum that are adamant about fog lamps not being a problem. They're wrong and are probably a road hazard to others.

[gspannu]

Originally Posted by 493263

Because fog lamps and high beams have very close angles. In other words, it doesn't dip down at a steeper angle than low beam. You don't need to have them both on at the same time.

That's why you're not supposed to use fog lamps in normal driving condition because fog lamps can still blind people from far away in the opposite lane. The only reasons why it's not as distracting as high beam is because it's generally a weaker output bulb and it's placed very low to the road.

There's a few people in this forum that are adamant about fog lamps not being a problem. They're wrong and are probably a road hazard to others.

I doubt these are such a road hazard. If they were, legislation would not allow fogs/ high beams in UK or Europe.

I guess it is US legislation based on some early laws - automotive laws are usually the last to be changed; and do not really keep up with technology.

A similar example was the Adaptive LEDs and Xenons - these were launched in UK/ Europe without any limitations, but in the US, the lights were launched without the Adaptive bit; and it took a while for BMW to get the necessary approvals.

[493263]

Yes the US legislative process is slow. It's not a big deal with 25W halogen fog lamps but you know people will put higher output bulbs in there. LED fog lamps are starting to pick up. Some also install HID fog lamps. I see it more and more often. It's infuriating when you're blinded by these lights. A quick google will show you a mixed perspective. The people saying it's not a problem probably drive SUVs/Trucks or they are the ones with the unreasonably bright fog lamps.

Seriously, fog lamps blind other drivers more than it helps you see the road more. It's angled near horizontal, not dipped down like your low beam.

[m_alnimah]

Originally Posted by 493263

Yes the US legislative process is slow. It's not a big deal with 25W halogen fog lamps but you know people will put higher output bulbs in there. LED fog lamps are starting to pick up. Some also install HID fog lamps. I see it more and more often. It's infuriating when you're blinded by these lights. A quick google will show you a mixed perspective. The people saying it's not a problem probably drive SUVs/Trucks or they are the ones with the unreasonably bright fog lamps.

Seriously, fog lamps blind other drivers more than it helps you see the road more. It's angled near horizontal, not dipped down like your low beam.

I agree! But if it's a Little Car that's pretty much Superglued to the road I don't see why Fogs will be a Problem...