Lum's guide to proper fog light use

Lum

It's that time of year again, there is a whisp of fog at rooftop level therefore some plonker will have their front and rear foglights on dazzling everyone around them, and two weeks later when the fog is cleared they will still be at it, hopefully some of them might read this...

Rear fog lights

Highway_code_rule_226 wrote:

You MUST use headlights when visibility is seriously reduced, generally when you cannot see for more than 100 metres (328 feet). You may also use front or rear fog lights but you MUST switch them off when visibility improves (see Rule 236). Law RVLR regs 25 & 27

Highway_code_rule_236 wrote:

You MUST NOT use front or rear fog lights unless visibility is seriously reduced (see Rule 226) as they dazzle other road users and can obscure your brake lights. You MUST switch them off when visibility improves.
Law RVLR regs 25 & 27

This is pretty simple. Can you see other road users or road furniture 100 metres away if so, turn your rear fog lights off. If not, go ahead and use them.

Not law but some additional points.

Is there another car following you? Has it seen you? By this I mean it's keeping it's distance and isn't about to drive into the back of you. If so turn the rear fog light off so as not to dazzle them. Check your mirrors regularly (you do do this when driving anyway, right? right?) when the car behind goes away, turn them back on again!

Is it raining? If so then it is not foggy! rain has this wonderful effect of refracting and scattering light, and foglights which are particularly bright suffer badly from this. If you can still see the car in front then all turning your foglight on is going to do is dazzle the driver behind and make it much harder to judge your position and speed turn them off!

Front fog lights

Ok, so some cars, usually German ones, are hardwired so that the front fogs have to be turned on before the rears. In this case there isn't much you can do about it. I don't like whoever designed your car but just follow the rear fog light guide above, no situation exists where you should have your front fogs on but not your rears.

Can you see past the end of your bonnet? If so you probably don't need your front fog lights on.

What happens in severe fog is your own headlights reflect off the fog in the air, obscuring your view of the road ahead. Turning your full beams on only makes this worse. In this situation you might notice that turning your headlight off actually improves matters and you can see further, if so try turning your front fog lights on. A properly designed front foglight will shine low down, attempting to illuminate the road underneath the fog. If this improves visibility for you then great, drive on sidelights and fogs. Chances are you wont be able to go much above walking pace in this situation.

Note that some cars come with a different sort of front foglight, they don't shine under the fog, but they use some kind of filter, typically yellow, that doesn't suffer from reflection. If you have a car like this then some situations exist where visibility is improved even at higher speeds by driving on sidelights and fogs. It might not be legal to do this so do so at your own risk. If the fog is really that bad then you're unlikely to be seen doing it.

Final thoughts

On some cars the fog light switch is a latch that remains on even after you have stopped the car. Remember to turn the damn thing off at the end of the journey. Don't be that plonker who, 2 weeks after the fog has gone away, is still driving around with their rear fogs on dazzling everybody around them.


Comments and constructive criticism welcome.

prowla wrote: »

you are allowed to switch them on and off multiple times during a journey if the conditions change.

banger9365

here here 1+ on that

TrickyWicky

Thats a mighty fine post. You have no idea how irritated I get by w@nk£rs with their fog lights on for no apparent reason. It's sheer ignorance and disrespectful to other motorists.

I've been driving for 5 or 6 years and only ever actually needed to use my foglights genuinely 4 - 5 times.

photome

TrickyWicky wrote: »

Thats a mighty fine post. You have no idea how irritated I get by w@nk£rs with their fog lights on for no apparent reason. It's sheer ignorance and disrespectful to other motorists.

I've been driving for 5 or 6 years and only ever actually needed to use my foglights genuinely 4 - 5 times.

I have been driving for 30 plus years doing over 30000 miles a year for a lot of that time and havent used my fogs many more times than you.

Problem is none of the w@nk£rs (as you put it) will be reading this thread

muckybutt

But its cool to have yer fog lights on innit :cool: .....said in jest cos I detestthe whankers that leave them on as well.....dont forget the stupid turn assist function as well where they turn one side of your fog light on when you turn corners, in my eyes thats !!!!in stupid, if you cant see enough with normal driving lights on to turn a corner then get off the bloody road....damn krauts have a lot to answer to

prowla

Rear lights are a right pain in the backside; they should make it a law that they all cancel when you turn off the engine or that you get an audible warning for leaving them on.

The common sense thing with them is that you only need them if you can't clearly see the shape of the cars in front.

...and you are allowed to switch them on and off multiple times during a journey if the conditions change.


OTOH, what is the issue with front fog lights?

Apart from looking a bit of a plonker having them on, do they cause any problems?

They are lower down than the car's headlights and don't shine upwards to dazzle oncoming drivers.

I sometimes use them when driving along a country lane, as they help show the edges clearer.

(I also used mine the other day when one of my headlight bulbs went.)

Sgt_Pepper_2

If you can't see past the end of your bonnet should you be driving?

bugslet

I think this is the first time I've thanked everyone in a thread!!!

Drives me nuts, well it must do as I'm stuck behind someone shouting, ' What do you think I can't see you, you Numpty!':rotfl:

Mrs_Imp

Sgt_Pepper wrote: »

If you can't see past the end of your bonnet should you be driving?

Sometimes it's unavoidable. I did the Snake Pass one winter's night. Halfway over, we hit thick fog. It wasn't safe or practical to stop. I ended up driving at walking pace with DH looking out of the side window watching the edge of the road, I kept a close eye on the centre white line, while watching for oncoming cars. Not my favourite journey ever. It wasn't helped my the idiot who raced up behind me, then didn't like that I was going so slowly, so he bunged his full beams on. I had to stop completely, as all I could see was his light reflecting off the fog in all directions.

I do use fogs in heavy spray on the motorway if I find the cars in front of me disappearing.

worried_jim

I agree with all the comments, but I can can recall a time when I was on the M1 in the densest Nottingham fog I can remember when all of a sudden this Alfa Romeo comes like a ghost out the mist doing the ton with no lights on what so ever. I slowed to about 40mph to give this nutter plenty of time to get well ahead of me- scared the living daylights out of me.

maninthestreet

There are some people who will insist on using their front fog lights as a matter of course when it's dark, because they mistakenly believe they are driving lights.