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-   -   The DRL Thread: Everything about daytime running lights (https://www.team-bhp.com/forum/technical-stuff/131947-drl-thread-everything-about-daytime-running-lights.html)

Note from Mod - this thread was carved out of the Ford Ecosport thread hence some headings or references might be apparent.

Just curious. Apart from the looks, is there any real utility for the DRLs in Indian conditions, that cannot be satisfied by parking lights?

I guess it could be a bit more effective in fogs. But I do NOT really think it's required in most parts of India.

The main function of DRL is to be easily spotted by other motorists on the road. It's important that you not only be able to see others vehicles, but also be seen by others. It doesn't matter which country you are in. Make sure that the DRL isn't too harsh, but just enough to be seen. Works the best especially during dawn and dusk.

I was always wondering what the DRLs are for, but the above doesn't make sense to me.

If the main function of the DRL is to be spotted by other motorists, then what are the headlights for? Are you saying that headlights do not perform the function of being seen by others? That's wrong. Or that they are seen by others but can be harsh?

Thanks in advance.

OT: The function indeed is better visibility in daylight. Compared to regular headlights, the benefits are less power consumption, no glare etc. I believe in some countries in Europe DRLs are now mandatory by law. It looks quite ornamental because the manufacturers are getting quite imaginative with its implementation :)

The headlights are for night driving. The DRL (Daytime Running Lights) are for use during the day.

DRL's turn on as soon as you start the car. They will turn off when you switch on your headlights. Incase of BMW, Audi, they remain ON even at night since they look wicked. :)

Long time ago the headlights were used as DRLs. It was an option to have them turned on when the engine was running (~300 dollars for some cars)

Looking at the way the DRLs are being designed (especially by the VW group) they seem very ornamental. I would prefer a slightly bigger rectangle or squarish light setup.

DRLs are not foglights.

Is it because people in most parts of India have very sharp eyes?:)


DRLs are light sources that will indicate the presence of a vehicle during day in not so lit environments. Example, twilight time, inside tunnels, fog, snow, etc. If the driver doesn't turn on the lights, the car could remain invisible. DRLs ensure they are visible all time. But DLRs are not supposed to illuminate anything, so don't try to use them as headlights or foglights.

Headlights illuminate the roads during night and they are switched off during day. The DRLs cannot be switched off. They are on when the ignition is on. That is why they are called daytime running lights.

Why is it wrong? Do you keep your headlights on all the time? DRLs are always on, they can't be switched off.

BTW, I am talking from experience. My 1998 Chevy Malibu had DRLs. It was not a separate light, but function of the headlights. When I turned on the ignition, the headlights came on at fractional power. They remain on all the time. But when the night came, a sensor sensed it and turned on the headlights to 100%. As a result, I never had to turn on the headlights in my 30 months of ownership of that car. When I upgraded to Acura 3.2TL after that, I found it quite irritating that I had to turn on headlights at night manually.:uncontrol

Need to persist because it still does not make sense. During the day sunlight does a good job in India throughout the year almost everywhere.

1. For twilight, you can switch your headlight on a little earlier.

2. For fog, the objective should be to throw your beam as far as possible because visibility is poor. Fog lamps do that job.

3. For inside tunnels - I presume you mean long enough for daylight to not permeate, (though the tunnels I've been had bright tunnel lights), you can have automatic headlights coming up like the one on your Malibu. Because in that case you need light to illuminate and as per you DRLs are not meant to illuminate. So DRLs are not needed here.

What I said was wrong was the implied claim that "headlights do not perform the function of being seen by others". I do not know the rights or wrongs of DRL. I am yet to be convinced it's needed.

From what you said above, it is the sensor that would turn on the lights automatically that you missed in the Acura and not the DRL.

Cheers,

Have you ever noticed how certain colours seem to disappear in the heat haze on highway driving? This is where DRL's help most.

Not everybody does this. People assume that since they can see another vehicle approaching them, the driver of the other vehicle can also see them. This is so not true in a lot of scenarios.

DRL's are not for fog. From my experience they are most useful on cloudy and overcast days and when it is raining heavily. I have experienced this first hand on a recent drive down from Goa in the rains. Again sadly, not many people have the sense to switch on headlights in heavy rain.

Agreed that tunnels may be a weak example, but have you noticed how vehicles approaching you seem to disappear when you are exiting a tunnel and your eyes are still readjusting to sunlight? DRL's help here and they help a lot.

DRL's are not necessary, but they are damn useful in my opinion.

Let me elaborate on my rain driving experience on the highway. At 3:00 in the afternoon daylight was like what it would normally be at around 6:00 - 6:30 in the evening. To this you add rain and you know how quickly visibility goes down. Sadly not all drivers switch on the headlight when visibility falls.

During this kind of visibility it is really difficult to see dark coloured (gray, silver to name a few colours) vehicles which are still some distance away on the horizon. But with DRL's even these vehicles become visible, or at least you are aware that there is some sort of vehicle there. DRL's increase the visibility of vehicles over longer distances.

For example a silver colour car in the rain without DRL's would be visible let's say at 100 meters. The same car with DRL's will be visible from 200 meters on. Note this is just an example and not real life figures.

So in ending I say again, DRL's may not be necessary but they really help in increasing a vehicles visibility distance.

You can switch it on earlier for sure but what if you forget to turn it on in twilight and only switch it on when dark. Higher the risks in twilight of not being spotted. The idea of DRL is so that the driver doesn't forget they are always on.

Agreed that in India where sunlight is bright it's ok but early mornings and twilight are equally important.

Ah you missed this thread completely. Look at Rehaan's post with the pics:

https://www.team-bhp.com/forum/ownin...ml#post3024098

The farther the throw of beam the lower the visibility in Fog.
What if your car does not have automatic headlights? That's where the DRL will continue to remain ON.

DRLs are popular in Europe because the weather and natural lighting is such. While you do have sunshine even at 8 pm during the Summer, the Sun sets quite early in the Winter. Add to that torrential rain and fog, and you'll find yourself driving in gloomy conditions more often than not. That's why DRLs are popular. At least, this is my take on this.

Yes, it may seem silly in a country like India where you have sunshine for the most part of the day. DRLs have become a fad rather than a necessity.

But DRLs still serve the purpose of being noticed, and I don't see anything wrong with that, even if the weather and natural light is good.

From what I've understood, fog-lights are meant to illuminate the area right in front and around the front of the car. The distance / throw of light is not important. They are meant to brighten the area in front of the bumper, the area that otherwise isn't covered by the regular headlights.

I might be wrong.

Wow no. Maybe I need to be more attentive next time :)

True, but a DRL may not make the driver of the other vehicle see you any more than when a headlight does not make him do so.

Yes, I agree that DRLs will help here, maybe do a better job than a headlight because a headlight will "blinden" the vehicle on the other side. Many people, including me, use hazard light, which I also find equally serving the purpose, though may not be meant for the same.

Sure and thanks!

Agree and I think what you said in the end makes sense in certain circumstances.

I had missed it (as is usually the case) read it now. I never recommended using high beam for increasing a vehicle's visibility during fog, though Rehaan's post beautifully explains why. I said use a fog lamp as it throws your beam as far as possible.

Sure. I thought fog lights indicate your vehicle's presence to oncoming and vehicles coming from behind (if you have a rear fog lamp) in a fog. So it has to travel as far as possible. That's why I reasoned it should be a beam parallel to the ground.

Cheers,

Using hazards while driving just to indicate that you are driving slowly in rain/fog or tunnel is one of the biggest mistakes one can do. The sole reason for hazard warning lights is to indicate to the other road users that your car has broken down and you are stopped.

Exactly the opposite. The idea of the fog lamp is to provide illumination just a few metres in front of the vehicle and not farther away. The fog lamps in most cars are not used to see in fog but just so that oncoming traffic can see your vehicle.

The link i posted has more details on how the fog lamps work as well.

Both assumptions are totally wrong.

I drive my Jeep a lot in fog, so I have really working foglights in my Jeep.

http://www.team-bhp.com/forum/4x4-ve...ml#post2032763

Fog light is for illuminating the immediate front and edge of the road. They must have very short and very wide throw.

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