3 replies to this topic

[minialbania]

I have come across this a few times. In my opinion they are the same thing but can anybody tell me if there is a difference between the 2?

Thanks

[nicklouse]

spot lights light up the distance (driving lights). fog lights light up low and wide so as to not blind the driver.

[Dan]

Spot lights, driving lights, long range lamps, pencil beam lamps etc. are all broadly the same with some minor differences to the beam shape and are legally classed as auxiliary main beam headlamps. They give you much more light over a larger area and/or longer distance than normal headlamps, for night driving. They let you go quicker at night essentially, because you should never be driving so fast you can't stop inside the lit area in front if the car really.

Fog lamps or foul weather lamps are physically different in that as said above they aim the beam low. To clarify what's said above they avoid blinding the driver of the car they are fixed too, rather than oncoming traffic, because their beam hits the road and reflects up into the fog and rain from below. This helps you to see through it because light aimed straight at it will just reflect back at you and then you can only see white. They are meant to be used in place of, rather than along with, your dipped beam headlamps. They provide light close to the car. They tend to be misused badly.

[Cooperman]

When I first started driving we used to have real 'pea-soupers' as very thick fog used to be known.

The fog lights put out a very wide, short range flat beam which got 'under' the fog and enabled the driver to see the side of the road. With fog like that the dipped headlights gave too much light 'throw-back', so they were switched off. If a speed of 30 mph could be achieved one was doing well and sometimes 20 to 25 was all that was possible. I can even remember when I used to cycle, a bus driver asked if I would lead him from Hatfield to St. Albans.

I wonder what these 'fashion accessory' fog-lights as fitted to modern cars are supposed to be for. I have them on my BMW and have never used them.