Driving In Fog

ramkya1 · 2nd December 2005, 10:16

Hai BHpians,

In today's newspapers we have news of an accident due to fog on the Ahmedabad-Baroda Expressway of a speeding car and 4 people dying on the spot. With winter on and fog a problem in many places..... it would be useful to discuss safe driving habits in fog? I have some doubts......

1. What colour fog lamps are best..... white or yellow?
2. What other precautions to take while driving in fog ?
3. What about usage of horns in fog?

My cousin in Grimsby, England says even the horn is used with caution in winter fog ... they honk only once and in short blasts if they have to use it.

What say you Bhpians?

--- Ramky.

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tsk1979 · 2nd December 2005, 10:48

Color :
Yellow is the better. Ideally red is the best because red wavelength scatters the least.
However fog lamps should be low mounted and make sure your headlights are dipped. At full beam the fog will reflect the light and you wont see a thing.
Make sure your tail lamps are working
Another thing is speed. Try to follow the car in front with a safe distance. If thats not available and you cant see anything, crawl at 10-20kmph. Never go fast. I once banged into a divider since I did not heed that warning.

As for the horn, its useful if you feel that you are entering a junction and all. Short blasts can warn cyclists etc., who in non foggy conditions also are a big hazard.

zenx · 2nd December 2005, 10:52

Good points.
Also, if visibility is really low - u could keep ur hazard lights on - drove out of Kodai for about half an hour in extreme fog once. The blinking lights are more visible and catch attention of oncoming/following vehicles easily.
Straighten up ur seat and get close to the windscreen.
If you cant see for even a car length plus gap ahead of you - then stop for a while (with lights and hazards on)

ramkya1 · 2nd December 2005, 11:35

Quote:

Originally Posted by tsk1979

Color :
Yellow is the better. Ideally red is the best because red wavelength scatters the least.
However fog lamps should be low mounted and make sure your headlights are dipped. At full beam the fog will reflect the light and you wont see a thing.
Make sure your tail lamps are working.

When we used to rally for Popular back in 87-90's, everyone used yellow hella fog lamps. I read somewhere on the web in a technal section that yellos light is as good a white (will try to post the link soon)......... but never heard of red fog lamps. Yes.... it would be useful for warning, may be not enough to show you the roads?

-- Ramky

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tsk1979 · 2nd December 2005, 11:51

In dense fog nothing except the mercedes S class will show you the dangers. However the more towards "Longer wavelenghts you go" the more people can see you. Blue scatters the most, red the least, thats why train stop signals and intersection signals are red.

Infact if you go to an eye testing center, you will see that below the chart there is a yellow and red light. Opticians hardly use it due to ignorance, but that has a special significance. You see both those lights have the same strength from a measurement point of view. But to a normal eye red should appear brighter than green. However if your eye number is -1, and you put in a -1.5 or higher powered glasses, while you will be able to read the chart after straining your eyes, the green light will start appearing brighter. This is how the opticians should figure out that a higher number has been given than required.

Coming back to the point, to a normal eye, the red light will appear brighter than green when both have the same lumens strength. Also in fog, red will scatter the least. Since red also appears as tail lights of vehicles, red fog lamps are risky. So yellow-orange lights are good and if fog is too dense use your hazard lights too.

Max · 2nd December 2005, 12:07

what fog lights actually do ??? will it be visible at a distance in the fog to opposite light vehicle ? sorry, I have never driven in fog light conditions :(

tsk1979 · 2nd December 2005, 12:15

1. They make you see the road slightly better
2. Oncoming vehicles can spot you from further away. I have driven in fog where headlights of oncoming vehicles were visible only when they were few meters away. this problem is more prominent in day fog. But in day fog you see atleast little bit of road which vanishes in night completely

ramkya1 · 2nd December 2005, 12:23

Quote:

Originally Posted by tsk1979

1. They make you see the road slightly better
2. Oncoming vehicles can spot you from further away. I have driven in fog where headlights of oncoming vehicles were visible only when they were few meters away. this problem is more prominent in day fog. But in day fog you see atleast little bit of road which vanishes in night completely

2 weeks back from Cooner to OOty we had visibility of 10 feet in thick fog and were practically crawling up. Some sections we had to actually stop the car...... go forward to see if road was there at all. When oncoming traffic ws flashing thier hezard lights we could make them out, otherwise the headlights and fog lamps were not visible at all until they reach very close to you.

-- Ramky

Technocrat · 2nd December 2005, 12:28

Hi Guys I had posted a topic on this long time back, may be it can be of some help

INFO : Tips on driving in Fog

http://www.team-bhp.com/forum/showthread.php?t=3739

ramkya1 · 2nd December 2005, 12:46

Quote:

Originally Posted by Technocrat

Hi Guys I had posted a topic on this long time back, may be it can be of some help

INFO : Tips on driving in Fog

http://www.team-bhp.com/forum/showthread.php?t=3739

Hai Techno,

Tnx for that link, I think that coves it....... I did'nt know there was a thread.

- Ramky

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sbasak · 2nd December 2005, 15:07

Red fog light sounds strange!

We have red lights only at the back of cars.

Yellow fog lights are most common.

2nd December 2005, 10:16	#1
ramkya1 Senior - BHPian Join Date: Oct 2005 Location: Palakkad, Keral Posts: 1,826 Thanked: 431 Times View My Garage	Driving In Fog Hai BHpians, In today's newspapers we have news of an accident due to fog on the Ahmedabad-Baroda Expressway of a speeding car and 4 people dying on the spot. With winter on and fog a problem in many places..... it would be useful to discuss safe driving habits in fog? I have some doubts...... 1. What colour fog lamps are best..... white or yellow? 2. What other precautions to take while driving in fog ? 3. What about usage of horns in fog? My cousin in Grimsby, England says even the horn is used with caution in winter fog ... they honk only once and in short blasts if they have to use it. What say you Bhpians? --- Ramky. -----------------------
	() Thanks

2nd December 2005, 10:48	#2
tsk1979 Team-BHP Support Join Date: Feb 2005 Location: San Jose, CA Posts: 23,717 Thanked: 22,825 Times View My Garage	Color : Yellow is the better. Ideally red is the best because red wavelength scatters the least. However fog lamps should be low mounted and make sure your headlights are dipped. At full beam the fog will reflect the light and you wont see a thing. Make sure your tail lamps are working Another thing is speed. Try to follow the car in front with a safe distance. If thats not available and you cant see anything, crawl at 10-20kmph. Never go fast. I once banged into a divider since I did not heed that warning. As for the horn, its useful if you feel that you are entering a junction and all. Short blasts can warn cyclists etc., who in non foggy conditions also are a big hazard.
	() Thanks

2nd December 2005, 10:52	#3
zenx Senior - BHPian Join Date: Oct 2004 Location: Bangalore Posts: 1,161 Thanked: 158 Times View My Garage	Good points. Also, if visibility is really low - u could keep ur hazard lights on - drove out of Kodai for about half an hour in extreme fog once. The blinking lights are more visible and catch attention of oncoming/following vehicles easily. Straighten up ur seat and get close to the windscreen. If you cant see for even a car length plus gap ahead of you - then stop for a while (with lights and hazards on)
	() Thanks

2nd December 2005, 11:51	#5
tsk1979 Team-BHP Support Join Date: Feb 2005 Location: San Jose, CA Posts: 23,717 Thanked: 22,825 Times View My Garage	In dense fog nothing except the mercedes S class will show you the dangers. However the more towards "Longer wavelenghts you go" the more people can see you. Blue scatters the most, red the least, thats why train stop signals and intersection signals are red. Infact if you go to an eye testing center, you will see that below the chart there is a yellow and red light. Opticians hardly use it due to ignorance, but that has a special significance. You see both those lights have the same strength from a measurement point of view. But to a normal eye red should appear brighter than green. However if your eye number is -1, and you put in a -1.5 or higher powered glasses, while you will be able to read the chart after straining your eyes, the green light will start appearing brighter. This is how the opticians should figure out that a higher number has been given than required. Coming back to the point, to a normal eye, the red light will appear brighter than green when both have the same lumens strength. Also in fog, red will scatter the least. Since red also appears as tail lights of vehicles, red fog lamps are risky. So yellow-orange lights are good and if fog is too dense use your hazard lights too.
	() Thanks

2nd December 2005, 12:07	#6
Max BHPian Join Date: Jun 2004 Location: Thane Posts: 538 Thanked: 98 Times View My Garage	what fog lights actually do ??? will it be visible at a distance in the fog to opposite light vehicle ? sorry, I have never driven in fog light conditions :(
	() Thanks

2nd December 2005, 12:15	#7
tsk1979 Team-BHP Support Join Date: Feb 2005 Location: San Jose, CA Posts: 23,717 Thanked: 22,825 Times View My Garage	1. They make you see the road slightly better 2. Oncoming vehicles can spot you from further away. I have driven in fog where headlights of oncoming vehicles were visible only when they were few meters away. this problem is more prominent in day fog. But in day fog you see atleast little bit of road which vanishes in night completely
	() Thanks

2nd December 2005, 12:28	#9
Technocrat Senior - BHPian Join Date: Feb 2004 Location: GTA Posts: 14,813 Thanked: 2,700 Times	Hi Guys I had posted a topic on this long time back, may be it can be of some help INFO : Tips on driving in Fog http://www.team-bhp.com/forum/showthread.php?t=3739
	() Thanks

2nd December 2005, 15:07	#11
sbasak BHPian Join Date: Nov 2005 Location: CCU-LTN Posts: 608 Thanked: 14 Times	Red fog light sounds strange! We have red lights only at the back of cars. Yellow fog lights are most common.
	() Thanks