Now that winter is coming, When it comes to a vehicle’s lighting and driving in fog it is often a source of great frustration and annoyance amongst road users to see the misuse of thisFog Lamps: When Should they Be used? particular safety feature. It is a growing problem that road users are unaware of the mechanics of fog lights ie what they do, how they work, and most importantly when to use them because more often than not these unaware drivers use them as a means to increase they’re own visibility to other drivers in good visibility conditions which is of course not their intended function.


How they work: Fog lights differ from headlights in that they are designed to illuminate your peripheral field of vision(Area right in front of you such as the lines on the road) in poor visibility conditions such as fog and snow, unlike headlights which are designed for long range illumination. Fog lights are located low down on the bumper close to the ground to take advantage of the fact that fog tends to hover about 12 to 18 inches off the ground and it is this pocket that fog lights are designed to capitalise on and brighten. Though being positioned so low down has the unfortunate consequence of exposing them to damage from road hazards like stray pebbles, Kerbs etc but the tradeoff in safety is worth it in spades.

Fog Lamps: When Should they Be used?

That being said the lens thickness of fog lights tends to be a little bit denser to increase durability and reduce the replacement requirements over time which is good because depending on the make of your car replacement parts could be expensive.

 

What not to do:

 

  • A big no-no although it may seem like the smart move at the time it cannot be emphasized enough that using your high beams in foggy conditions is a terrible idea, without 4going into the nitty-gritty science of it all the reason it is a terrible idea is because when light hits a particle of water(which is what fog is) light refracts off it spinning off in every direction creating a wall of light in front of you (similar to if you shine a light on a disco ball) and as fun as that sounds it will only result in creating a wall of glaring light in front of you decreasing visibility even further and blinding road users in front of you and in the oncoming lane which isn’t going to make for a great time. It will also induce some serious road rage that nobody wants to be on the receiving end of.
  • Another big no-no which might actually not register with many people and has been reported to be on the rise is people using fog lights when there are no adverse weather conditions. This is because having them on can potentially blind other road users as fog lights are designed to be incredibly bright.
  • Never use HID(High-intensity discharge) sometimes referred to as xenon bulbs in your standard reflector fog light housing. The reason being is these bulbs shine too brightly and need projector foglights to control the light they emit.

It is important you don’t be this guy!

Fog Lamps: When Should they Be used?

It is also worth noting it is currently an offense to misuse your fog lights which can incur penalties.

With respect to fog lamps Road Traffic (Lighting of Vehicles) Regulations (S.I. 189 of 1963) states: (8) Where a vehicle equipped with a fog lamp within the meaning of article 44 of these Regulations is used in a public place, such lamp shall be used only in fog or while snow is falling. Penalties for misuse of fog lights are €1,000 in the case of a first offence and Fog Lamps: When Should they Be used€2,000 in the case of a second, third or subsequent offence
So it is recommended you make sure you are properly using your fog lights at all times to avoid this guy getting on your case!

 

Things to watch out for: These days it is becoming increasingly commonplace for cars to come equipped with automatic fog lights which turn on as soon as the car senses there is fog and turns off when the fog has passed, unfortunately when it comes to automation computers don’t always get it right, Fog sensors work by detecting changes in the ambient light which is light that is all around you. However, external sources of lighting such as street lights could fool the computer into thinking there is no fog and as a result dangerously leave the lights off.

 

It is recommended that you operate the lights on your car manually especially the Fog which handily enough has its own universal symbol on the face of the button.7

As super complicated as it sounds, Don’t forget your car also has a rear fog light!!The RSA recommends a combination of dipped headlights with fog lights on.8

Improper alignment, It is also imperative that you have not just your fog but also your headlights and rear all properly calibrated to comply with local road safety laws.
It is recommended that you get a qualified mechanic to fit lamps instead of doing it yourself as the illumination beam could be skewered and aimed into the eyes of oncoming traffic.

 

Things to be aware of:
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Clear or Amber? A few years ago it was a law in France that all fog lights had to be amber tinted as at the time they believed this led to greater fields of visibility, however this has since been disproved and in actuality the use of clear fog lights has been shown to produce the same levels of illumination if not better when compared to amber, this is down to the fact that manufacturers of amber fog lamps put an amber coating over the clear which reduces the brightness by as much as 25%

 

What Bulbs do I use? Two commonly discussed bulbs are Halogen and HID.

HID(High-intensity  discharge) bulbs also referred to as Xenon are sometimes retrofitted to the original housing of a fog lamp and whilst the light that comes off it may have a cool blue hue to it it is very likely that the Fog lamp is now misaligned as HID bulbs burn more intensely and are not designed to be housed in reflective lamps but were designed to be in projector style lamps which controls and focuses the output. As well as this they also zap more power from the battery and all this for a light intensity that is largely redundant as high-intensity bulbs are generally meant for distance illumination and not peripheral.

Furthermore, while you may but probably won’t pass the NCT or random garda checkpoints if you got into an accident it is most likely insurance companies will use the modification to void your insurance as they will look for any excuse not to pay out and that’s something nobody wants.

Halogen bulbs are cheap and are the industry standard for most car models. They also provide more or less the same amount of peripheral illumination required without the concerns of proper/improper housing.

Rear fog lamps: Rear fog lights are always behind the red perspex on a rear lamp cover as to not confuse drivers and pedestrians with the reverse light. Sometimes there is only 1 Rear fog light and 1 Rear reverse light though this varies from car model. But the light on the driver’s side is always the one that is wired and will illuminate, sometimes there are two fog lights installed on the rear to maintain symmetry it is not recommended you wire this one up.

Lamp condition: Since the fog lights performance is dependent on how efficiently they illuminate poor conditions it is wise to make sure they are clean as they can get dirty quickly being positioned so low to the ground, it has been shown that light output can be reduced by as much as 50% from dirt alone.

Where can I get fog lights? Easy! At www.micksgarage.com we stock a wide range of fog lights for nearly every car model so if you are driving in an old scirocco or a new bmw X5 we will be able to provide you with the highest quality fog lamps.

  • Des

    The law regarding the use of front fog lights is ridiculous and should be amended. Rear fog lights and front fog lights perform totally different functions and should not be viewed the same. Front fog lamps (as mentioned in this blog) enhance visibility directly in front of the vehicle, they DO NOT ‘blind’ other road users. Whens the last time you were ‘blinded’ by the factory fitted front fog lamps of an oncoming vehicle?…… If anything, we should be encouraging motorists to use their front fog lamps at all times. It doesn’t effect other road users in any way…. but it does make an oncoming vehicle easier to see if they have them on, INCREASING road safety. These are facts!

    • Johannes van Zyl

      Would agree to that – parking lights together with front fogs on are less disturbing than dipped main beam and front fogs on. Could then take the place of “DRL’s” for vehicles not such equipped. Also to be used under other poor visibility conditions – e.g. rain, smoke (fires), dust (gravel roads) – up to discretion of driver then to use dipped main beam together with front fogs. Rear fogs only to be used under really poor visibility conditions – causes much more disturbance to fellow drivers than front fogs. (when used in otherwise clear conditions)