# Luxeons as daytime running lights?



## Entropy (Jun 6, 2003)

Interesting idea: While Luxeons are currently not economical for automotive illumination use. (You'd need $200-300+ worth of 5W emitters), what about use as a daytime running light, whose purpose is merely to be visible rather than illumination?

Even at a lower power, a Luxeon might make a significantly better DRL than a standard headlight since it's a very small and intense source, rather than a source with a much larger area but lower intensity.

My car doesn't have DRLs, but I habitually turn my headlights on to improve visibility to other drivers, giving effective DRLs, but I'd like to save on main bulb life by using Luxeons for the DRL functions.


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## Alaric Darconville (Jun 6, 2003)

You might want to check www.lightsout.org for some info on DRL's and their relatively small impact on safety. There's a bit in there somewhere about how DRL's only reduced the number of *nighttime* accidents...


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## Entropy (Jun 6, 2003)

Looks like some people just being plain bitter. (Not necessarily you, but that site seems a bit whiny.)

I'm sure there are just as many studies proving advantages of DRLs, although I do have a few comments.

"1. The original concept for DRLs was to compensate for a lighting deficiency. We don't have such a deficiency in the United States!"

These people must live in Arizona. If they lived in the Northeast they'd know about such things as clouds and tree cover.

"2. Since we have greater natural light, the auto manufacturers have increased the intensity of their DRLs. Just what we need: Bright lights hitting your eyes while you're trying to drive a car on a busy highway!"

I'll agree with them here. High-beam DRLs is a bad idea, both because it's annoying and because it burns out bulbs faster. I always use low-beams during the day, and what I was asking about was an even DIMMER solution. (Essentially using Luxeons as front-facing "super indicator" lights.)

"3. Safety features need not create hazards and, more to the point, should not be so very, very annoying to so many people. Humans, by our very nature, tend to avoid disturbing stimuli, thus taking our eyes off the road! Some people respond to DRLs by avoiding looking directly at other cars on the road. Some avoid using their rear- or side-view mirrors. Some are even using devices which are already on the market to reduce the glare from oncoming DRLs. These actions by people will result in them being less observant, therefore, worse drivers and more accident prone."

Same basic gripe as #2.

"4. Current data on the safety benefits of DRLs has been misinterpreted by proponents of DRLs. They have absolutely no positive effect on bright sunny days. The data should be interpreted thusly: People are not turning on their lights in conditions requiring illumination -- e.g. rain, snow, fog, dusk, dawn, etc. -- and therefore the problem is driver error. The solution, logically, should be driver improvement."

I'm sure there are plenty of counterstudies to this. There have been plenty of situations where I have wished that oncoming drivers had DRLs. (For example, green car with green vegetation behind it, driving through the woods.)

"5. Of all the myriad categories of motor vehicle crashes, DRL use is arguably associated with improving one, maybe two types. The better solution to highway safety is driver improvement; this would substantially and dramatically decrease accidents of all types."

Driver improvement is nice, but it's not gonna happen. Some people will drive like idiots, no matter how you try to educate them. Some have the "I'll drive however the $#(@()# I want" attitude. (Again, the people protesting this obviously don't live in the Northeast.) And why not have the DRLs for those few cases (See above, such as car color that blends with background) where even the best drivers might have trouble?

Should we not install airbags because 95% of drivers will never get into an accident?

"6. People will literally die because of DRL use. By failing to institute the correct solution to problems illustrated by DRL data -- driver error -- people will continue to die and be injured who might otherwise have been spared from such incidents. Furthermore, we believe the annoyance and distraction caused by DRL-equipped vehicles will be significant, but we also believe this will never be admitted or assigned to DRL use by their proponents."

Again, it's an issue of proper vs. improper DRL implementation. I'll agree that some DRL implementations (HIDs going full blast for example) are REALLY damn annoying. But there have been a number of cases where I've been glad that an oncoming driver had their halogen low beams running.

"7. DRLs are an inefficient use of resources. Lights will have to be replaced more frequently, and it will have to be done by auto service personnel. Fuel consumption will increase and, although it's not much per car, it is an astronomical dollar figure when multiplied by the millions of vehicles in this country. Conservative estimates place the figure at 604 million gallons of fuel per year, resulting in 8 billion pounds of CO2 being exhausted into the atmosphere. What's even worse, in testing vehicles for fuel efficiency, GM has requested -- and received -- permission from the federal government to disconnect DRLs so as not to be penalized for poorer fuel efficiency. So consumers are not able to know how DRLs will affect their fuel efficiency when buying a car. See NHTSA's correspondence with the EPA regarding DRLs' CAFE exemption."

Which is why I want to use Luxeons. Lower power consumption and virtually infinite life. Plenty of heatsinking opportunities on a car. /ubbthreads/images/graemlins/smile.gif Also, what makes DRLs so hard to replace? I have never had problems replacing the headlight bulbs in my car, and I am certainly not "certified service personnel".

"8. DRLs represent stone-age technology in the 21st century. Since cars do not need illumination at all hours, why not install sensors to activate headlights when ambient light is insufficient? The technology exists, and is already in use on several vehicle models."

I plan on eventually doing this for my main lights, but I still want DRLs for daytime situations where even low beams are overkill.

"9. DRLs are insulting to our intelligence. DRL proponents assume that drivers are not intelligent enough to know when to turn on their lights. By implication, then, DRL proponents are saying, in effect, that the states are licensing unqualified drivers! Driving is a skill. Observation is a skill. With proper experience and training, these skills are integrated in the person of a safe driver. Both of these skills can be nurtured or improved in every driver. But, neither skill will be enhanced in today's environment if it believes safety lies in the gadgets and misinterpreted data. Safety, in reality, is nothing more than the collective responsibility of each individual to be the best driver -- the most observant, the most cautious, the most defensive, the most skilled -- that he or she can be. "

People can sometimes forget. 99.9% of the time, I habitually turn on my lights whether it is daytime or not. But once or twice (Often after getting gas), I have forgotten. To err is human, and no one is perfect.


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## 6pOriginal (Jun 6, 2003)

I think it's generally a good idea to have DRL. It gets very foggy at times in the area where I live during summer. While most people will turn on their lights, some don't, they either forget or don't care. There are times that you wouldn't know there's a car there if it wasn't the lights, the visibility was like less than 50 feet. I think the problem is not totally about DRL, but out of calibrated headlights/fog lights, and high beam DRLs was a bigger issue. Just like HID, if they are probably calibrated, I don't find them any more annoying than normal halogen lights. I think the key is to have the lights properly calibrated and may be reduce the power when using DRL.

Just my 2 cents /ubbthreads/images/graemlins/smile.gif


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## PhotonBoy (Jun 6, 2003)

We have DRLs in Canada and I think they're a great idea.

The problem for car manufacturers is simple: *cost*

Only when the cost of supplying LEDs is equal to or less than old-fashioned incandescents will they switch to them.

This might happen sooner than not, since incandescents need to be replaced, requiring access panels, etc. which also increase cost.


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## highlandsun (Jun 6, 2003)

In my own driving, I use my high beams like once every 6 months. I think that the average driver uses their low beams far more often than high beams, so using high beams for DRLs makes sense. When I was still using sealed beams and H4s, the low beam always burned out while the high beam filament still looked perfectly new. Pointless waste. (My car has hi/low in a single fixture.)

Also, if the DRL is really being used *in the daytime* then the high beam is not going to be any more glaring than a low beam - either one is dwarfed by ambient sunlight.

Personally I'll go with the whiners - poor driver education is a social problem. Social problems should be solved by social means, not by technological gadgets.

If you want DRLs, then I guess Luxeons are one approach. As I recall, DRLs just run the lights at half power, so around 27-30W. On my car, the Canadian models had the factory fog lights wired as DRLs. So we're not talking about a particularly bright light here. You could probably do something decent for a couple of watts.


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## Bob Snow (Jun 9, 2003)

I am always shocked at how many people are driving in the rain or after sunset with no lights. It seems to me that circumventing this is the primary effect of DRLs on accident statistics. A better solution for dealing with people who just don't get it, would be a simple photo sensor and a sensor that detects rain on the windscreen to automatically turn on the lights. Both exist in some luxury cars and would at least turn on the lights to the rear of these cars, an issue not addressed at all by DRLs.

When I purchased a big BRIGHT red Audi back in 86, it was my first car with a high mounted center brakelight. I got rear ended twice in that car. I was convinced the Tornado Red paint and center mounted red light were attracting them!


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## Entropy (Jun 9, 2003)

[ QUOTE ]
*PhotonBoy said:*
We have DRLs in Canada and I think they're a great idea.

The problem for car manufacturers is simple: *cost*

Only when the cost of supplying LEDs is equal to or less than old-fashioned incandescents will they switch to them.

This might happen sooner than not, since incandescents need to be replaced, requiring access panels, etc. which also increase cost. 

[/ QUOTE ]
Well, my plan was to do this myself as a retrofit, which is why I originally placed it in Homemade and Modified. In other words, asking the modifiers if they thought it was a worthwhile project and if they had any ideas/suggestions.

Also, I don't think thes highbeam DRLs are running half-power - I have never seen a DRL that was as orangish-red as a dimmed incandescent would be. (An advantage to general LED headlighting in the future - Easier to dim.)

Yes, many of the situations where DRLs are beneficial can be cured by social change, but there are situations where even the best of drivers benefit from having/other people having DRLs. It's the same deal as with LED vs. incandescent brake lights - Only a fraction of a second in reaction time can make the difference between an accident and a close call. If a green car is coming around a bend in the woods, no matter how close attention you are paying, your brain WILL process it much earlier if it has DRLs. In fact, you may see the DRLs through breaks in the woods when the car itself would normally be camouflaged.

And as I said - Social change would be optimal but it is simply not possible. Anyone who thinks it is should try driving on the Garden State Parkway... There are simply too many people with the attitude of, "I have money, I can afford a few speeding tickets/lawyers fees."


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## highlandsun (Jun 9, 2003)

Hm.... I'll reconsider; my car's factory fog lights came with 881 bulbs - 27W, 540lumens. You would need 5 LuxeonVs to match that output - no power savings to speak of.


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## Entropy (Jun 10, 2003)

[ QUOTE ]
*highlandsun said:*
Hm.... I'll reconsider; my car's factory fog lights came with 881 bulbs - 27W, 540lumens. You would need 5 LuxeonVs to match that output - no power savings to speak of. 

[/ QUOTE ]
I'm wondering how much is REALLY needed to simply "be visible"

My answer - Not much for people looking straight at the light source. Look at older red LEDs - They put out almost insignificant amounts of light that weren't even suitable for illumination at a distance of more than 2-3 feet in total darkness, but were perfectly visible from across a brightly lit room or more if you were looking directly at it.

Especially since the energy coming from the Luxeon is concentrated into a very small area compared to the area of most headlights.

I guess a good experiment for someone would be to take a 5W white Luxeon flashlight down a road a bit and point it at someone an appreciable distance away - Is it bright enough to attract attention, even though it might not do a single thing to illuminate anything.

Might even try it with my 1W Luxeon just to see how it works.


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## highlandsun (Jun 10, 2003)

Having already gone through the exercise of converting my front turn signals to amber Luxeons, I'd suggest using them for your experiment. Especially since you're now talking about testing with a 1W instead of a 5W part, the ambers are twice as bright as the whites, and the color itself is more distinctive.


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## MenaceSQL (Jun 10, 2003)

Highlandsun, how did you wire everything up?


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## Entropy (Jun 11, 2003)

[ QUOTE ]
*highlandsun said:*
Having already gone through the exercise of converting my front turn signals to amber Luxeons, I'd suggest using them for your experiment. Especially since you're now talking about testing with a 1W instead of a 5W part, the ambers are twice as bright as the whites, and the color itself is more distinctive. 

[/ QUOTE ]

Interesting suggestion, although my "testing" in the short term would simply involve someone at a distance holding my BadBoy white. 

http://www.lumileds.com/pdfs/an1149-1.pdf was linked to from another thread - Specs DRLs at 40 lumens.

So 3 1W whites (or maybe 2 white and an amber , maybe only one white, to reduce apparent color temp, which is easier on oncoming drivers' eyes) would do it.


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## highlandsun (Jun 11, 2003)

That app note also shows that a DRL has a *minimum* lit surface area of 40 square centimeters, and a max intensity of 7000cd. You may need some diffusing optics to meet this requirement.

MenaceSQL: see my "Luxeon Turn Signals" thread in this forum or my web page http://home.attbi.com/~hyc/


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## MenaceSQL (Jun 12, 2003)

Thanks /ubbthreads/images/graemlins/wink.gif


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## Kristofg (Jun 12, 2003)

It might be worth looking at a light sensor to turn on the luxeons during day time when passing trough a shaded area. I've seen the new renaults use this system and when they drive trough shaded tunnels or under bridges their lights come on whilst they are in a darker area. I actually like this as it makes the car much easier to spot and it saves on power consumption during the bright sunlight. One thing I really hate is the way volvo has implemented those permanent yellow markers on the side. I always have the impression they are signaling that they want to make a turn (direction indicators have to be yellow over here) and you have to keep looking at their indicator a few seconds to note that it's not blinking but constant on as a marker light.


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## NightShift (Jul 5, 2003)

I just got my Blaster III a few days ago and I wanted to see how it looked from far away in the daylight, (also thinking of this thread) and woah - the thing is insanely bright and noticeable. It looks like HID light. I think the 1 watt luxeon w/ the 30mm optics would work great as DRLs and it's only consuming 1 watt - ~700mA compared to halogen DRLs that look disgusting and get so hot! It's not blinding like u cant see anymore, but it will definately make u stand out.


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