http://dms3000.dot.gov/docimages/pdf82/176157_web.pdf

Note: This is a 66 Page *.pdf document.

:mad:

thats outrageous

It's about time. Those lights blind oncoming traffic.

I'll read the meat of it tonight. But it looks like basically they did one-on-one intereviews with elderly americans to determine what is glaring. THey even say there evidence is anecdotal, but they still talk like this is proven. :rolleyes: Also, many of the elderly people saw any bluish light, no matter how intense it was, as glare. Meanwhile in Europe, nobody seems to mind. Let's see if there any scientific evidence in the doc tonight.

Hey if the light bothers geezers that much they shouldn't be driving at night anyway. :devil:

It is about time!!! I can't remember how many times I almost ran off the road Because Duma$$ sportin HID lights blinded To me there a hazard they need to get rid of them the sooner the better.:monkey: HID lights

That isn't a DOT document. As far as I can tell, it's a document written by a consultant for a study commisioned by the DOT.

Don't jump to conclusions.

It's just wierd that the rest of the world uses HID's with no problem. I don't run them, but that's becuase I can't afford it!

I used to think HID's were pointless (didn't have a problem with them as they never seemed too bright to me) until I drove a friend's Acura TL.... the difference is amazing. The whiter light produced makes everything much clearer. I actually noticed that the beam doesn't project as far, but because it is brighter and clearer, nearly the entire illuminated area is more visible and thus more usable.

First off, I am not for or against HIDs. I have never driven a car with them, and do not have a problem with the glare they produce.

Well, the problem is not with the fact that any car has HIDs that cause a glare problem. It is the design of the headlight unit itself. The BMW HID design does not produce glare, where as the Audi HID design produce a large amount of glare. But, if a few car manufacturers have units that produce glare and the rest do not. Then they focus on the bad units to base there study on. Kinda like the 1 trouble maker in class that ruins it for everyone else in the class.

This is a government study done for the NHTSA & DOT. That is why the study document is so freakin big.

More (Shorter) Articles Worth Looking At:
1. http://www.usatoday.com/money/autos/2002/05/06/headlight-complaints.htm
2. http://www.4x4wire.com/access/notices/sema/sema_headlights.htm
3. http://money.cnn.com/2002/05/16/pf/autos/safety/
4. http://www.energy.ca.gov/pier/buildings/lighting_research/LRC%20Partners%20Day%20May%20'02/Glare&HID%20Headlamps.pdf
5. http://www.canadiandriver.com/news/010927-3.htm
6. http://www.thecarconnection.com/index.asp?article=5133&n=156,241&sid=241
7. http://dms3000.dot.gov/docimages/p62/133584.pdf

i love my HID's and will attack anyone that tried to take them from me.

From the PDF:


Vehicles with high-mounted head-
lamps currently enjoy an “unfair ”see-
ing-distance advantage that comes at the expense of severe glare to drivers
of lower vehicles. Linking aim declina-
tion to headlamp mounting height is
an easy and effective way to materially
reduce glare from high-mounted head-
lamps,and will have an equalizing ef-
fect upon the seeing distance available
to drivers of all vehicles.See Attach-
ment 3,pages 17-21.


Damn SUV's!

Chieh
--
Chieh's Web - http://Chieh.CameraHacker.com/

This document does not ban HID headlamps, but decides what to do about the un-controlled HID lamp usage in US:


Question 6:Should the U.S.adopt the HID glare control measures of automatic leveling and washing that have been adopted by Europe?Please identify the data and analyses that support your views.What costs would be incurred to do so?


Chieh

After reading the "Recommendation" section of that PDF (Page 39 of "Where Does the Glare Come From? / Page 57 of the PDF), I don't see any mentioning of banning HID lamps. There are many good recommendation on how to make HID more glare-friendly in future vehicles.

After reading the article, I think there are many good reasons why HID should become standard among all vehicles . . . making HID mods pointless. Maybe people would start modding their car with old yellow bulbs. 8-)

Chieh

Yeah, bascially the recommendations were to change the US spec to be more like European and Japanese standards which use more of the light for sight and less for glare. They want to make all hids auto leveling and the beam angle dependant on height. I didn't know trucks and SUVs in other countries had a height dependant declination angle. Good ideas ...

Well, if you ask me the US DOT will ban them. Because all they can do is screw something good up. Like a steel ball with a rubber hammer. Just think of all the good cars overseas we od not get in the US because of the DOT.

For Example:
1. Porsche will not sell the 911 GT3 in the US because the DOT wants them to change the bumper height less than 2 CM. And Porsche is not going to do it.
2. There are several Turbo Deisel engine not offered here because the grade of Deisel fuel we use in the US is subpar to that of what they use in Europe.
3. Panoramic side view mirrors are illegal in the US. These are the mirror you find on many German cars. They are flat on 3/4 of the mirror and the outside 1/4 curves away from the car.
4. I am not going to argue this one, but the emissions in the US are striker than anywhere else. Case in point '02 & '03 WRX, 3 Cats, 1 Resonator, 1 Muffler and some other black box in the back.
5. Clutch/Starter Lockout switch. What happens if you need to move the car with the starter to get it out of danger.

Q) why d european countries not have a problem with HID's?

A) Most european countries spend countless millions on lighting streets at night. In England for example a law was passed years ago that by 2010 all Motorways where to be lit. Which reduces glear 100X. And another reason is only the USA has such a large number of SUV's to the number of cars.

Originally posted by daytontp
3. Panoramic side view mirrors are illegal in the US. These are the mirror you find on many German cars. They are flat on 3/4 of the mirror and the outside 1/4 curves away from the car.


Actually I seen them on my friend's Saab

Were they stock or did he buy them and install them later. I have them on my WRX, and I bought them afterwards.

Originally posted by Wheels
Q) why d european countries not have a problem with HID's?



Also, according to the doc, the beam patterns on Euro spec lights are more focused and spill less intense light to oncoming drivers. There's two problems I think in the US. Unregulated HIDs and HID knockoffs including HID-look bulbs that throw even more glare, and SUVs that have the same beam angle as cars which puts the light right in my friggin eyes! Grrr :monkey:

They better not ban them:mad:

I will take that glare for the cool look of HID. I was planning on ordering some Muchullas (<--Spell check) for my STI lights.

:mad:

It isn't about selfishness, it's about safety. If some blinded senior runs into your new car because your HIDs caused them to lose control, what price your fancy lights now?

I was contemplating HIDs, but upon realizing how well my Prodrive headlights work, I'll spend my money on something else, thank you.

European cars, for the most part, and certainly if they have HIDs, have projector lenses. There are good and bad ways to design projectors, as evinced by (good) Mercedes and BMW, and (bad) Audi and Acura, the latter who persists in putting HIDs in reflector housings.

European roads are indeed lit much better, which is why their headlamps tend to have such a sharp cutoff. They just don't have to light as much of the road. That high, wide DOT pattern is some of the reason HIDs in the States are such an issue.

Even were U.S.-spec cars to get the leveling switches that every European car has, think about how many people over here would forget to lower their lights. Heck, think about how many people here don't even have their headlights properly adjusted? :eek:

While banning them would seem draconian, it really is a safety issue, even if it doesn't affect any of us. Remember, we aren't always going to be young (or relatively so, in my case). It's never a bad thing to have compassion.

Much of the difference that people see with HID is indeed attributable to the whiter light that is available. But as with any spectrum color change, that whiter light comes with downsides, like decreased effectiveness and increased glare in the rain, and the like.

We haven't heard the last of this one, and banning HIDs seems as silly as mandating digital television, but...

Kevin

Never mind my palsy...

Kevin

My question is the longterm effects of these lights on vision. Having to look at these things in on coming traffic countless times I have to wonder if this is affecting my vision in some way. IMO is no different than staring at the arc in electric welding and everyone knows that is no good for the eyes.:mad:

The light from arc welding is much more intense and includes a lot of UV rays. HIDs only emit visable light.

Originally posted by mtb_dude
The light from arc welding is much more intense and includes a lot of UV rays. HIDs only emit visable light.

I Would still like to se a spectrograph of the light it emits though.

Sorry for all those I blind, but I LOVE my HID's. I love them so much I am having my foglights custom retrofitted to have HID bulbs as well. :D

From the doc



Aftermarket lamps produce glare in all the same ways
as original-equipment lamps,but also present additional
issues:
• General consumer ignorance regarding the purpose,,
proper mounting,aim,electrical connection and
appropriate use of fog lamps,driving lamps and sup-
plemental low beam lamps,resulting in deliberate or
inadvertent inappropriate installation and use,
• Wide availability and low price of poorly--made lamps
not compliant with any construction and/or pho-
tometric standard and bearing no (or fraudulent)
certification marks,
• Wide availability of very intense driving lamps that
may be deliberately or inadvertently used in traffic.


In short, get a good system clearly marked as HID approved and aim them correctly :D

I think it is about time they did smething these lights are annoying and looking off to the side of the road to avoid blindness is almost just as dangerous. Something also needs to be done about these stupid RICERS buying foglights from Wal-Mart and not aiming them toward the ground. The idea for FOG lights is to illuminate the road below the fog not to illuminate a road sign and my face. So if you are gonna use Fog lights make sure they are aimed properly.

just my .02 cents

This document was prepared by Daniel Stern who sells aftermarket bulbs and lights. He has some very good knowledge of SOME of the issues, but no real scientific knowledge. He depends on data and results from other people's studies, but really is not qualified to either do research on his own, or to evaluate whether other studies are done properly or relevant.

While I'm sure he knows far more about lighting than most people, I find some of his conclusions suspect. In particular his electronics and physics seem rather lacking. The document has been available on his website for at least 6 months. Now the DOT is also listing it - as it was submitted to them. Let's hope some good scientists review it carefully.

Originally posted by daytontp

4. I am not going to argue this one, but the emissions in the US are striker than anywhere else. Case in point '02 & '03 WRX, 3 Cats, 1 Resonator, 1 Muffler and some other black box in the back.
What does a resonator, muffler or black box have to do with emissions? I'm pleased that newer cars are required to be clean. 99% of the public doesn't know or care about the few hp they lose, and in exchange we get healthier air. :)

Paul

They don't, but I could not find anything on that black box in the Service Manuals. I am with you on this one. Personally, I prefer cleaner air. Living in SC, a state that does not do annual emissions tests on vehicles, I see a good number of cars driving around that are burner oil and it gets blown out the exhaust. Especially Chryslers and Toyotas. Some of which are less than 3 years old.

I'm the author of the 66-page PDF document given at the top of this thread under the heading "US DOT to ban use of HID headlights". I don't know who posted it, and I'm not sure where s/he got the idea that the US will ban HID headlamps...certainly the idea did not come from my document, which was written in response to the National Highway Traffic Safety Administration's request for comment on aspects of headlamp performance and glare. It's as if the original poster didn't read the document at all.

Some of the other ideas posted in this thread are a lot closer to a real understanding of the issue, regarding the differences in beam pattern and equipment (autolevelling, etc.) and aim standards. Some of the assumptions regarding the reasons for these differences are not quite right (there is no "high and wide DOT beam pattern", and European headlamps produce *more* light on the road surface, DOT lamps produce less, for instance).

--Daniel J. Stern

Originally posted by Alan
This document was prepared by Daniel Stern who sells aftermarket bulbs and lights. He has some very good knowledge of SOME of the issues, but no real scientific knowledge. He depends on data and results from other people's studies, but really is not qualified to either do research on his own, or to evaluate whether other studies are done properly or relevant.

While I'm sure he knows far more about lighting than most people, I find some of his conclusions suspect. In particular his electronics and physics seem rather lacking. The document has been available on his website for at least 6 months. Now the DOT is also listing it - as it was submitted to them. Let's hope some good scientists review it carefully.

Alan, what do you know of my (extensive) body of scientific knowledge? How about my participation in the Federal Transportation Research Board's visibility symposium this past June, were you there? Is your critique based on your opinion of my presentations to that forum? Perhaps you refer to my peer review of papers submitted for the Transportation Research Board international convention in Washington DC this coming January...have you a beef with the reviews I've done? Or the glare roundtable I'm on the steering committee for?

I'd be interested to know which "conclusions" of mine you find "suspect", and which "electronics and physics" you find "lacking". Please elucidate; I'd love to clarify any misunderstandings you may have and hear any arguments you may wish to raise...as long as those arguments are founded on solid data and science, as mine are.

As far as good scientists reviewing the document carefully: You betchya. Many of them. Government scientists, industry scientists, research scientists...and I haven't had anyone yet come back to me and say that it came to "suspect" conclusions and was "lacking" in proper understanding of physics or electronics. So please share your objections as well as their basis and your credentials.

DS

Originally posted by gtguy
I was contemplating HIDs, but upon realizing how well my Prodrive headlights work, I'll spend my money on something else, thank you.
European cars, for the most part, and certainly if they have HIDs, have projector lenses. There are good and bad ways to design projectors, as evinced by (good) Mercedes and BMW, and (bad) Audi and Acura, the latter who persists in putting HIDs in reflector housings.
Even were U.S.-spec cars to get the leveling switches that every European car has, think about how many people over here would forget to lower their lights. Heck, think about how many people here don't even have their headlights properly adjusted?
Kevin

Kevin, you've hit on what should be obvious, but escapes many people: It's not that HID headlamps are better than halogen ones. It's that good headlamps are better than bad headlamps. REGARDLESS of what light source is used in them!

But there's nothing wrong with reflector-based HID headlamps *if* they are designed properly. In fact, reflector HID headlamps are often considerably less glaring than projector HID headlamps, because of the much lower unit luminance of the visible optic components. In plain English: The HID burner produces a given amount of light. You, the oncoming driver, will see the projector OR the reflector illuminated by the burner. If the projector or the reflector is small, the amount of light per unit surface area will be higher. If the projector or the reflector is large, the amount of light per unit surface area will be relatively lower. As with any other headlamp, the primary factors in performance and glare are the the photometric characteristics of the headlamp in question (the beam pattern it produces) and the attainment and maintenance of the correct aim. ANY headlamp, misaimed vertically, will be glaring (too high) or ineffective (too low). HID headlamps, due to the very high levels of flux (light), and the intrinsically-glaring nature of the light from current automotive HID burners, will be generally more glaring than halogens if misaimed or badly designed.

I agree with you on manual headlamp aim correctors; I'd like one in my car and I'd love one in my truck, but I don't think I'd want this equipment in the hands of most North American drivers. Note that manual aim correctors aren't allowed on HID headlamps in Europe; they must be automatic.

--DS

Originally posted by 128d
Sorry for all those I blind, but I LOVE my HID's. I love them so much I am having my foglights custom retrofitted to have HID bulbs as well. :D

Doesn't sound like you're "sorry" at all for the roadway danger you're creating.

Originally posted by sternlights
Alan, what do you know of my (extensive) body of scientific knowledge? :lol: BURN!!! :lol:

(warning: rant)

I must be smoking the wrong crack or something. What is so blinding about natural light? Are old people automatically attracted to shiny bright objects? Why are they staring at it? Just my random thought: BECAUSE IT'S DIFFERENT AND THEY'RE NOT USED TO THEM.

These poor old people have been seeing the same yellow, orange, candle-colored lights for their entire lives. You throw a different temperature bulb at them and they're mesmorized at the wheel -- as are some of my friends. Why do you have to stare at the lights of an oncoming car? I'd be willing to assert that if you stare at the lowbeams of every passing car, it'd cause you to crash, but you don't because you automatically look "away" from the light, and thus continue on your way.

But when you see the blueish hue from HID's/xenon, it's something your brain is typically not used to seeing (unless you live in Europe...) so for whatever reason, your eyes want to automatically "look over and check it out" -- thus the "those damn HIDs are blinding!?!?!?!1111!!"

And as far as the claim about the Audi's, I'm going to have to get my ULTRA crack pipe with dealer-cut rat poison out for that one. My friend just put clear corners on his S4 and he wanted to see how much he needed to aim them. So I pulled up my stock suby to the same wall as he did -- wheel to wheel, neck and neck, and what did I see??

His beam pattern was sharp as could be, about a foot lower than mine (STOCK). His was cut low on the left (read: oncoming traffic side where the drivers head would be) and rose up slightly to the right with a TIGHT cutoff pattern, displaying light where road signs would be and lighting up directly in front of (and slightly to the right) of the car.

Mine?? Well, mine were sorta scattered all over the place like my lights were somehow aimed using a few rounds with a paintball gun. There was random reflections in odd places, and they shined much higher (vertical, not intensity) on (yes the low beam) settings than the S4 xenon's, and clearly went further over into the oncoming traffic lane. (read: oncoming drivers face)

As there hasn't been an uproar in Europe about these satanically influenced blue lights, I would venture it's a safe bet that us Uhmericans are simply not used to it. I would definitely agree that SOME people do not have aftermarket HID's aimed correctly, and they should be stopped and fined for it because it's dangerous. But like so many things, there seems to be a need to devise a government "solution" to a problem that only seems to exist in our country.

My advice? Don't stare at the oncoming Acura/Audi/BMW/Lexus/Mercedes/Mini/Porsche's lights if you think it causes temporary blindness.

now excuse me while I go try and "go blind" the other way...

(end rant)

phew. that felt better. (sorry if I offended anybody)

Originally posted by CirrusWRX
(warning: rant)

I must be smoking the wrong crack or something. What is so blinding about natural light? Are old people automatically attracted to shiny bright objects? Why are they staring at it? Just my random thought: BECAUSE IT'S DIFFERENT AND THEY'RE NOT USED TO THEM.
As there hasn't been an uproar in Europe about these satanically influenced blue lights, I would venture it's a safe bet that us Uhmericans are simply not used to it.

You're off-base here. First off, the light from HID headlamps is by no means "natural". The spectral power distribution of an automotive HID headlamp is full of peaks and valleys, nothing at all like the continuous-line SPD of natural sunlight. The "Closer to natural daylight" hype is just that—hype.

Furthermore, one of the high peaks in the SPD of current automotive HID headlamps is in a frequency to which about 40% of the population is extremely sensitive. The thing is, this peak does nothing for the performance of the lamps. Talks are underway to see about closely identifying the boundaries of this peak and cutting it down in future HID headlamp burners; that will help a LOT.

The theory that drivers bitch about HIDs because they're "not used to them" has no basis in science; it is simply an excuse to avoid solving the real problems. The problems ARE solvable, and doing so will not reduce (and in fact will improve) the performance of HID headlamps. We just need the regulators and the industry to cooperate to get it done.

And there has been an outcry in Europe over HID glare, for the same reason. It's just that it hasn't been as much of an outcry as over here, because over there they pre-solved some of the problems we haven't addressed yet (beam pattern, explicit control of glare, self-levelling, headlamp cleaning).

DS

Originally posted by sternlights


Alan, what do you know of my (extensive) body of scientific knowledge? How about my participation in the Federal Transportation Research Board's visibility symposium this past June, were you there? Is your critique based on your opinion of my presentations to that forum? Perhaps you refer to my peer review of papers submitted for the Transportation Research Board international convention in Washington DC this coming January...have you a beef with the reviews I've done? Or the glare roundtable I'm on the steering committee for?


DS

We've been down this road before, and while I find MOST of your papers, conclusions and testimony to be fair and reasonable, I do have issues with some of the things you've said on the alt.autos.subaru newsgroup. And while I only have a couple of years as a Physics major and did NOT get my degrees in that field, I believe that you have not got a technical degree - if I remember right. While my credentials are not sufficient to propose technical solutions, I do not claim they are. You do. And while study of relevant materials helps to prepare one for dealing with technical standards and papers, it seems to me that formal training in optics, electronics and physics would be required.

As for specific disagreements, I'm sure you will remember that I have issues with your assertions that the wiring on our cars is inadequate. After having done the training and tests to get my FAA avionics certifications, as well as many years of electronics repair, I suspect I have at least as good an idea of what is satisfactory wiring as anyone. And I do not have any bias on what is usable, since I don't sell any aftermarket "upgrades".

But let's NOT get into a flame war, we have more ideas in common than otherwise. I agree that high mounted lights are a problem, as are poorly designed lights, as are many modifications that cause excessive glare. But I really don't have the technical credentials to make these assertions in a scientific paper. However to make a submission to the DOT formal credentials are not needed.

Originally posted by Alan


We've been down this road before, and while I find MOST of your papers, conclusions and testimony to be fair and reasonable, I do have issues with some of the things you've said on the alt.autos.subaru newsgroup. While my credentials are not sufficient to propose technical solutions, I do not claim they are. You do.
As for specific disagreements, I'm sure you will remember that I have issues with your assertions that the wiring on our cars is inadequate. After having done the training and tests to get my FAA avionics certifications, as well as many years of electronics repair, I suspect I have at least as good an idea of what is satisfactory wiring as anyone.


I back up my assertions with solid, accurate and reviewed science, and with real-world experience *in the relevant field*. I've had plenty of people come back and say "Y'know, I installed relays and heavy-gauge wiring in my Outback (Forester, Impreza, whatever) and even with the standard bulbs, the headlamp performance is obviously improved. I took voltage drop readings before and after and you were right, I found a significant reduction in voltage drop with the new wiring". You're the only one who's come back and said "I don't like that Daniel Stern, always talking about wiring and stuff. My calculations show that there's nothing wrong with the wiring, dammit."

So you may argue on a theoretical basis that the pathetic thin-gauge wiring in many new cars is perfectly adequate, but in the real world, you're just not right. I suppose it depends upon your definition of "adequate".


But let's NOT get into a flame war


When you choose to slam me in a public forum, you may expect a point-by-point response.


We have more ideas in common than otherwise. I agree that high mounted lights are a problem, as are poorly designed lights, as are many modifications that cause excessive glare. But I really don't have the technical credentials to make these assertions in a scientific paper.


Well, Alan, I do, and the intended recipients of that document (NHTSA) as well as other relevant parties (Transport Canada, UNECE GRE, numerous scientists and researchers from numerous other governmental and industry organisations) find my science proper and my conclusions reasonable. Whether NHTSA acts on my suggestions is not under my control, as there are a great many factors that organisation takes into account when writing regulations, aside from simple technical correctness. I was just in the office of Canada's lighting regulator yesterday afternoon discussing the matter, in fact. Often, regulators who *want* to fix things and rewrite technical standards to reflect the best science and the best practices are thwarted in those efforts from above, due to various different flavors of political pressure that can be applied from within or from ouside, or due to the limitations in scope of their (regulators') authority.

So, really, your having backed-off and acknowledged that my document wasn't full of shatz after all is kind of nice, but then why even slam it in the first place? Your objection to the scientific validity of my document is unique in that it's not shared by anyone whose opinion matters. You're welcome to your opinion of me and my work, but it sounds to me like a case of sour grapes or something.

DS

Daniel,

I find your point-by-point response does not include any illumination of your formal scientific training. Also, you seem to discount my previously stated MEASUREMENTS of the exact voltage drops in the stock Subaru wiring - at least in my 98 Legacy and my 02 WRX. Now if you want to fault the crappy bulb sockets - that's another story!

And while I'm sure many folks have told you of the visible improvements caused by adding in relays and wiring, I would recomend you look at the studies of cognitive dissonance reduction. Without measured, unbiased, objective experiments the anecodotal evidence is less than compelling. As any trained scientist would know.

Damn it, you're trying to do some positive things. Why not admit that ocassionally you might be in error?? It'll raise your credibility.

And you'll need to figure out some reason why you think I'm slamming your study - I'm not. I was just pointing out the source and limitations of it . As any one who reads critically and with proper skepticism should. Anytime I read ANY paper submitted by any source that is in an industry affected by the financial ramifications, I take that into account. Would you read a paper on sustainable logging from a wood products company, or one on energy conservation from an oil company without such knowledge?
That's all I was doing.

Originally posted by Alan
Daniel,

I find your point-by-point response does not include any illumination of your formal scientific training.

You're right. I refuse to play childish "My credentials can beat-up your credentials with one hand tied behind their back" games with you, Alan. I'm qualified to do what I'm doing, and those who have a genuine need to check 'em come away satisfied.

Also, you seem to discount my previously stated MEASUREMENTS of the exact voltage drops in the stock Subaru wiring - at least in my 98 Legacy and my 02 WRX. Now if you want to fault the crappy bulb sockets - that's another story!

As I recall, we had some "differences of opinion" as to the correct procedure and conditions for taking a meaningful voltage drop measurement when you professed to find no significant drop. The sockets are not "another story", they are part of the headlamp wiring.


And while I'm sure many folks have told you of the visible improvements caused by adding in relays and wiring, I would recomend you look at the studies of cognitive dissonance reduction. Without measured, unbiased, objective experiments the anecodotal evidence is less than compelling.


Certainly. That's first-year research methodology. But when those anecdotal reports show the same thing as isoscans made with a photogoniometer, well, they become just a *teensy* bit more credible. Your eye can't tell you "Hey, that hot spot that was at 17,635 candela with the original wiring is now at 19,822 with the new wiring!", but a before-and-after photogoniometric isoscan certainly can. But even without such tools, which are relatively difficult for the average person to get access to, it's a simple matter to rewire one headlamp and leave the other untouched, and switch them on for a side-by-side comparison. The results are patently obvious...in apparent intensity, in color temperature. This is not simpleminded "Gee, I just spent 40 bucks and an hour's time, so I guess of course it's better!" stuff like you get when pouring a bottle of Slick-50 into an engine.


Damn it, you're trying to do some positive things.


And I'm succeeding, if the feedback I'm getting from the people who matter in the field is any indication.


Why not admit that ocassionally you might be in error?? It'll raise your credibility.


When I am in error—which does happen, since I'm a human being—I admit it and take whatever action is necessary to correct the error. However, I am not in the habit of "admitting" to errors I have not made, and I have no intention of taking-up that habit.


And you'll need to figure out some reason why you think I'm slamming your study

Well, let's go back to your original post in this thread. You wrote:


No real scientific knowledge...Really is not qualified to do research on his own...conclusions suspect...physics and electronics lacking



That constitutes a slam of me and my document, and I am responding to it. Healthy scepticism is a good thing; gratuitous and idiopathic slamming is not. I have no intention of replacing any of the text in the document simply because you have baseless objections that are shared by exactly nobody who matters.


That's all I was doing.

Well, whatever. Personally, I don't care if people buy relays (or whatever) from me or from someone else. Truthfully, they're kind of a hassle. I make them available because it can be a challenge to find *good* components locally. If you seriously think I keep a roof over my head and groceries in my fridge by selling headlights or relays, you've never sold headlights or relays!

Now unless you have any objections...?

--DS

Not to fight anyone's battles, but it was obvious that the paper was written for those who are not scientists or engineers. It was written for legislators and commitee members. The paper was not meant to impress anyone on how good Daniel Stern is in math. That was a silly comment saying that he has yet to impress you with his math skills. Reading the document (all the way through like anyone who wants to comment on it should) you see that he appears to have a lot of knowledge about not only lighting, but impacts of it on people and traffic safety on an international scale. From the title of this thread, I thought I was gonna read one of those "family values" type gov't documents where they cater to the lowest common denominator and make the rest of the country suffer (kinda like speed limits :) ) That's not the case at all here. Also, it's nice to know that the guy who wrote this paper actually works in the industry, as long as conflict of iterest are kept in check.

I apologize for my scientifically baseless rant, as that is all it was, but I have a few questions then, as I am excited to learn more about this, so hopefully you can answer.

I think most HID's operate somewhere between 5000k-7000k, correct? I was under the impression sunlight was measured to be around 5250k (degrees, right?) So what you're saying that because the spectral power distribution has peaks and valleys that is what causes the "eye distraction?" Again, I'm learning here so this is not meant to be a "toungue and cheek" comment, but aren't colors recognized by their "peaks and valleys" at different wavelengths?

In other words, if the peaks and valleys were at different wavelengths for HID's, then they'd simply appear greener, or bluer, or redder, or oranger, etc... Is that correct? Or is it the case that "normal" head lights have a flatter, less "peaky" curve on a SPD scale??

With that in mind, this actually is a combination of engineering and biology, is it not? The levels at each wavelength will always be what they are, but the human eye perceiving them can differ from human to human, which is what I interpret as your "...one of the high peaks in the SPD of current automotive HID headlamps is in a frequency to which about 40% of the population is extremely sensitive..."

Could you expand on that a little bit? What do you mean by sensitive? Is it their brightness perception? Is it their color perception? Sensitivity sounds like it should be a good thing - quickly reacting to external stimuli, but I don't think I'm interpretting this correctly.

Now you mention that over in Europe they have solved some of these problems -- obviously the SPD peak that you refer to has not been addressed as we all use the same bulbs. But you mention beam pattern, explicit control of glare, self-levelling, headlamp cleaning... On just about all of the german cars (I'm referring to BMW, Audi, Mercedes) I can think of that come with HID (or the option for HID), they all have a VERY tight beam pattern and all come with self leveling (as they do in Europe.) I'm not sure what you mean when you say "explicit control of glare" but all the one's I have seen all have headlamp cleaning systems as well. (though the mfg's tout this feature as "headlamp washers for the snow" or something like that.)

So since these cars already have them, it sounds to me like our only resort to fix the problem is to change the "SPD output" (if that is a correct term?) of the bulbs or biologically alter people. (heheheh)

But in another question, since I didn't read all 66 pages of that report, did the ELDERLY people get a chance to drive with HID's? I think the greatest arguement happens to be people who don't have or have not experienced HID lights at night. It's one of those, "those lights are wretchedly blinding - we need to ban them." As opposed to "I drive with HID's and I can see in the dark better than I had hoped."

In other words, I think most people would agree that all situations aside, HIDs help you see better at night due in part (and lots of other factors) to their color. Now unfortunately, we have oncoming traffic to deal with, so it's not a blanket solution.

Here's one final thought -- what if EVERYBODY had HIDs and there was a manditory "upgrade" for everybody to have projector HIDs installed, aimed, and balanced on their cars in a 24 hour period.

Do the people who are "sensitive" to this temperature in question suddenly not have a problem anymore when they are instantaneously looking out their hood and see the color, and then see a car drive towards them with the same color?? I guess what I'm asking, is that this 40% of the population that is "sensitive" to this peak, can THEY see better using HIDs when they are behind the wheel?

(again, I'd like to stress the downfalls of text-bulletin boards that cannot convey the tone of voice I am using to ask these questions. I am truely interested in your responses, and I'm not just some ass asking you tongue-in-cheek questions to piss you off)

Mr. Sterns,

I appreciated your article and its treatise of headlighting issues. Not a bashing of HID headlamps or auto styling culture, but an objective, well-researched and documented paper on issues we ALL face on unlit two-lane highways and plausible solutions for them.

Moreover, I'm glad you were able to come in and defend yourself after inflamatory statements were made in seeming ignorance of what you were trying to say.

Even more, thank both of you for an enjoyable afternoon of vicarious flaming.

:lol: :lol: :lol: :lol: :lol: :lol:

Did someone mention that HID's look cool!!!!!:D :D :lol:

Originally posted by imprezton
[B
Even more, thank both of you for an enjoyable afternoon of vicarious flaming.

:lol: :lol: :lol: :lol: :lol: :lol: [/B]

You're welcome. Fun and games without even breaking the speed limit! :rolleyes:

Originally posted by CirrusWRX
I apologize

Forgiven, let's move on.


I think most HID's operate somewhere between 5000k-7000k, correct?


D2S/D1S (used in projector headlamps) runs nominally at 4150K.
D2R/D1R (used in reflector headlamps) runs nominally at 4250K.


I was under the impression sunlight was measured to be around 5250k (degrees, right?)


1) That's in the vicinity of noonday sunlight's Correlated Color Temperature, yes.

2) The expression is "Kelvin". The word "degree" is not used, even though the ° symbol is often used with the letter K. So "3400°K" is read "thirty-four hundred Kelvin".


So what you're saying that because the spectral power distribution has peaks and valleys that is what causes the "eye distraction?" Aren't colors recognized by their "peaks and valleys" at different wavelengths?


No, it's not because of the existence of peaks and valleys in the SPD, it's because of the location and amplitude of a couple of the peaks located in the short-wavelength (blue-to-violet) end of the spectrum. Colors are recognized not by their "peaks and valleys" so much as by the relative distribution of different-wavelength light. It's a fine distinction but a crucial one. The difference is between a continuous-line spectrum, in which the SPD is in the shape of a curve...these look like the graph of a mathematical function. A discrete-element SPD has distinct peaks and valleys, with gaps between them.

Blackbody radiators (anything heated to incandescence, including the sun or a filament) have continuous-line SPDs. If you place a color filter in front of such a light source, you will change the shape of the SPD curve, but it will remain a curve. If you look at an operating filament (or the sun, for that matter) through a slit diffractor, you will see a solid spectrum (a "rainbow").

Electrical arcs, such as those in the burner of an HID headlamp, are not blackbody radiators. They, like all electric-discharge lamps, emit light at various discrete wavelengths, depending upon the chemistry present in the atmosphere of the arc. Have you wondered why HID headlamps start out a deep blue-purple when first switched on, then go through a pink phase, a yellow phase, and eventually stabilize at their operating color? That initial blue color is due to the arc going through a pure-Xenon atmosphere. The Xenon, which is also the gas used in camera flashes, is there so that as soon as you turn on the lamps, you have SOME light. The heat of the arc vaporizes the metallic salts inside the burner, and this chemistry brightens the arc and adds more discrete wavelengths of emitted light to reach an aggregate emission that approximates "white". Without the Xenon, these lamps would take a LONG time to start up, like Sodium or Mercury lights in a street or gymnasium. If you look at an operating arc lamp through a slit diffractor, you will see discrete lines of color at varying distance from the central slit. Each color, no matter what its source, always appears a specific distance from the slit, so we have slit diffractors calibrated with the wavelength represented by each color. Each element has a specific wavelength at which it emits light, so it is possible to determine the chemical makeup of the arc environment by viewing it through such a scope.

But this is maybe a little outside the thrust of your question. It is particular wavelengths, in which automotive HIDs are very rich but halogens rather poor, that cause "blue light" (which I will not define for the moment, because it's not relevant) to stimulate a glare response in humans about 1.5 times the strength of the glare response stimulated by "white light". That is, the higher the amplitude of certain specific wavelengths of light in a given spectrum, the more glaring will be the light. To put it into "real world" terms, given an incandescent and an HID light source *of equal absolute intensity*, the HID light source will be 150% as glaring as the incandescent light source. Not only that, but if you place a blue filter ("Cool Blue" or "SuperWhite" bulbs, anyone?) on the incandescent light source, you also get increased glare, because by suppressing the yellow-to-orange light, you have increased the relative proportion of the blue-to-violet. The effect in this case is not nearly as strong as an HID light source that has blue-to-violet output "off the charts" relative to its other output, but it is nonetheless present.

The thing is, the shorter-wavelength light is relatively *UNhelpful* to seeing. The human eye sees very poorly under blue-to-violet light, because its short wavelength causes it to focus in a plane parallel to, but not coincident with, that of the retina. There is a *TON* of postprocessing that goes on between the retina and the brain that allows us to see blue-violet images clearly! So if the blue-violet were reduced through an alteration of the chemistry in the arc environment, the glare would decrease, even if the absolute intensity were kept identical.



Now you mention that over in Europe they have solved some of these problems -- obviously the SPD peak that you refer to has not been addressed as we all use the same bulbs. But you mention beam pattern, explicit control of glare, self-levelling, headlamp cleaning... On just about all of the german cars (I'm referring to BMW, Audi, Mercedes) I can think of that come with HID (or the option for HID), they all have a VERY tight beam pattern and all come with self leveling (as they do in Europe.) I'm not sure what you mean when you say "explicit control of glare" but all the one's I have seen all have headlamp cleaning systems as well.


The primary difference is in the photometrics (the beam pattern) and the initial aim standards. The European beam standard contains more stringent limits on glare light (light directed above the horizontal), requires higher seeing performance (higher minimum acceptable level at the "down the road seeing light" points in the beam) and requires a specific beam shape to minimize a certain kind of glare (the cutoff is "staggered", with the RH side of the cutoff located at the horizon and the LH side of the cutoff 0.5 degrees below the horizon, but both sides horizontal...the 15° upsweep to the right is NOT permitted). None of these provisions are present in the US headlamp standard, which treats all headlamps alike regardless of light source. That would be OK, but the glare limits present in the US standard are very high. It wasn't a problem until recently, because the glare limits were out of reach. Now we have high-intensity-discharge lamps and high-efficiency halogen lamps and we are playing with a LOT more raw light off the bulb than we were in the sealed-beam days when the glare limits were put into place, so these too-high limits are now within easy reach.

Also, headlamps are aimed higher in the US than in Europe.

Headlamp autolevelling is *permitted*, but not *required* in North America, same with headlamp washers. Both systems are crucial for minimizing glare. Many US-sold vehicles with HID headlamps have this equipment, but many do not. Not good enough!

One very important factor to consider is the optic factors. An HID headlamp can appear "paper white" or it can appear "police blue", or just about anything in between. The same goes for projector halogen headlamps. Due to the single-slit behavior of the edge of the cutoff shield in a projector beam, if corrective measures are not taken, there will be color diffraction at the cutoff of the beam. This diffraction can be manipulated to appear as practically any color that is present in significant degree in the source light. I can't prove it, but it seems to me that some manufacturers specifically request particular handling of this effect by the lamp makers. A lot of Audi projectors look extremely blue-to-purple from certain angles...even in the halogen versions! Take this concentrated blue-purple band near the cutoff (right where oncoming drivers' eyes will be) and you've got a good recipe for a distinctive "Hey, that's an Audi" appearance...and a lot of glare.

Also remember the previous point about unit luminance. For a given beam pattern and a given light source, the larger the illuminated portion of the operating lamp that is visible by an oncoming observer, the less will be the glare. The smaller, the greater will be the glare. Projectors have a very large disadvantage relative to reflectors on this front!


But in another question, since I didn't read all 66 pages of that report, did the ELDERLY people get a chance to drive with HID's?


Yes. There have been several really good studies done that have examined many aspects of the question you're asking. There is no clear advantage to HIDs over halogens from a driver performance perspective, whether the study subjects are young, old, or mixed. The effect holds in the presence or absence of glare. In fact, some HID headlamps give significantly *poorer* driver performance results than some halogen headlamps, due to simple photometrics. A lot of HID headlamps produce a ton of foreground light, but no more down-the-road light than any halogen headlamp. That wide, brightly-lit foreground brings high subjective-preference ratings for these headlamps, and it is very "comfortable" to drive with such wide foreground light...but the bright field of illumination right in close to the car closes-down your pupils and worsens your distance vision. This effect is *greater* for older drivers than for younger ones (which makes sense, since glare sensitivity tends to increase with age). The studies are ongoing, as science has yet to meet the phenomenon to which it responded "H'm, you know, I think we've studied this one enough", :^{)} but there are no missing links such as "What about elderly drivers? What if we give EVERYONE HID headlamps? What if the driver has halogens and the oncomer has HIDs? What if the driver has high beams and the oncomer has HID low beams?" etc.

CONTINUED IN PART 2

In other words, I think most people would agree that all situations aside, HIDs
help you see better at night due in part (and lots of other factors) to their color.


Nope! This would be a thoroughly inaccurate "agreement" indeed. Considerable "Closer to daylight!" marketing hype aside, there is no improvement in foveal vision (for this context: Down the road seeing, the most important kind for safety at speeds over about 30mph) with light of higher (bluer) color temperature. One study by Bullough and Rea reported a small (barely significant) improvement in peripheral vision with light of higher CCT, and this study was immediately picked up and trumpeted by a particular bulb company as "proof" that their Cool Blue halogen bulbs help you see better. In fact, the study "proved" nothing of the sort, and Bullough was mentioning to me the last time we spoke that if one wanted to optimize the peripheral vision improvement effect (which would still remain quite small!), one would want to increase the *green* component of the light, not the blue. Current HID lamps don't look green, however, so there's no market incentive for "Cool Green" headlamp bulbs. Speaking of market incentives, that's why HID headlamps look the way they do. A Sylvania engineer who was one of the team leaders of the initial development of the DC HID system that was used on a particular model of Lincoln in the late '90s prefaced his remarks at the 1998 SAE International Congress by pointing out that they could make HID headlamps pretty much whatever color they wanted to, and their first prototypes had an operating appearance very similar to that of a high-efficacy halogen headlamp...very WHITE. The response of the automakers was "Go away, nobody's going to pay three times as much for a headlamp that doesn't look any different, even if it works better". The SAE "White" boundary is *enormous* and allows relatively huge deviation from what any reasonable person would call "white"...it can be quite yellow, for instance, or quite blue and still be within the "white" standard. So...blue HIDs!


Here's one final thought -- what if EVERYBODY had HIDs and there was a manditory "upgrade" for everybody to have projector HIDs installed, aimed, and balanced on their cars in a 24 hour period.


This would solve nothing, see above.


Do the people who are "sensitive" to this temperature in question suddenly not have a problem anymore when they are instantaneously looking out their hood and see the color, and then see a car drive towards them with the same color??


Good question. Remember, there is a difference between signal light (what you see when you look at an operating lamp) and illumination light (that which permits you to see whatever the light is shining towards). One phenomenon at work here is scatter. The driver of an HID-equipped car is not looking at a concentrated spot of light with an SPD high in glare-producing wavelengths. He is looking at an area approximately 40 degrees wide by 15 degrees high illuminated by a lamp. Ever notice how from behind the steering wheel, everything appears pretty much white /normal with HID headlamps, but when you look at an operating HID headlamp, you get the blue appearance? "Payback time" comes in disturbed environments (rain, fog, snow, dust) when the scatter will be directed back towards the driver, who will get a large dose of those frequencies he normally doesn't see. (This, together with the high-foreground-illumination effect described above, is why the kid who's converting his fog lamps to HID is a moron.)


Note that one effect largely absent from the discussion is Color Rendering Index, or CRI. This is the metric of how accurately colors are rendered under a given light source, relative to a "noonday sun" standard that is specified in great detail. A CRI of 100 (or 1.00) is perfect. Blackbody radiators (incandescent lamps, specifically halogen headlamps) have a CRI of over 95, even the dim sealed beams that look piss-yellow compared to most other headlamps. The best automotive HIDs have CRIs in the mid 70s range. This is an effect of the discrete-line/noncontinuous output spectrum. There's no known detrimental effect to safety from using headlamps with a CRI of 74 instead of a CRI of 96, for instance, so I'm not trying to use this as a "Xenon headlamps are unsafe" argument. But it is worth noting that due to the difference in output spectrum type (continuous vs. discrete-line), CRI -- and NOT color temperature -- is the only realistic basis for comparison of HIDs to "real sunlight". And by that metric, they are much farther away from "natural sunlight" than halogen bulbs!

Think that's about enough for tonight.

DS

Sir - I wish to thank you for your absolutely wonderful responses. I just got back from vacation (which is why I did not respond sooner) but I learned a LOT from your writings, and I really hope some other people did too.

I want to read it again a few more times as I had a few additional follow up questions, but chances are you already "answered them in there" and it's just a matter for me to piece some more stuff together (I understand I will never "fully understand this" unless I make it my life, but just having a firmer grasp is what I was after and you certainly did that.)

Thanks very much for not "skimping" or "taking the easy way out" on my (probably n00bish) questions.

Kyle

The original poster, ME, did not read the entire article. I read some, and scimmed through some. But, I admit the first article should not have been posted with that Subject line. But, if you do a search on Yahoo or Google for "NHSTA HID", you will find a very large number of articles. Of which, some talk about the NHSTA wanting to BAN the use of HIDs in the US. But, I could not find anything in the main article or the NHSTA website about that.

I will admit, that if you want to find out as much info as you can on headlights, you need to read this article. I scimmed through it and it appears to be a very technical document.

Originally posted by CirrusWRX
Sir - I wish to thank you for your absolutely wonderful responses. I just got back from vacation (which is why I did not respond sooner) but I learned a LOT from your writings, and I really hope some other people did too.



I'd also like to thank you. I can't even believe how much I've learned about this. :D

the 15° upsweep to the right is NOT permitted).

Could you go into a bit more detail on this? This seems to be the way E-code headlights and DOT VOL headlights are according to your website last time I checked it. Some of us with 2002 Imprezas are getting projector type headlights with halogen bulbs that are of this type.(notably, "STI" Projectors(RHD and LHD, though RHD upsweep to the left(BAD!), UK300's, etc...)

Screw all this HID stuff. I want night vision, radar and sonar that sees out a mile or more and over hills and around curves and behind and to both sides etc and doesn't blind other drivers. Give me some of that secret stuff they used in Afghanistan. Satellite uplink to something that that has everthing below identified...............my own set of drones... lasers that zap deer and dogs when they cross the road in front of my car.

Face it the worlds supply of tungsten is running out!HID's don't use tungsten.One day even the cheapest car will come with HID light as OME.HID is the FUTURE!The same talk about HID's today,is the same talk that was said about hollowgens 20 years ago. CAN'T STOP PROGRESS!:devil:

Well, in that case lets use candles.

Stern Lights. Great info. This thread alone is a outstanding.

The HIDs that come mounted on cars from the factory are not a problem. They are usually well aimed and have a good cut off line with practically no spill. In fact, a lot of cars with halogens that have practically no cut off and are poorly aimed are some of the major offenders as well as improperly installed aftermarket HIDs and raised trucks with headlights higher than your roofline. Maybe we should start going after big rigs and busses too? The point is there are a lot more blinding done by cars with halogens than cars with OEM HIDs and people that constantly bitch about HIDs are just jealous!

As far as making them illegal - that will never happen. Look how many expensive cars are on the road today with HIDs. Recalling all those would not only be expensive but you will also have a riot on your hands since once you tried HIDs you will never go back!

And as far as the aftermarket kits go they are already illegal and explicitly state they are for offroad use only.

Love HIDs! :D

Holy Bump! Going on 4 years! I havent heard anyone bitch about HIDs in a while. I used to have a few friends that hated them but Im with you 0BlueSTi4, I love mine.

... lasers that zap deer and dogs when they cross the road in front of my car.

AND OLD PEOPLE!

its either that or we just send them into space: http://www.thebestpageintheuniverse.net/c.cgi?u=glenn

:devil:

Ehh they could ban em, they aren't really any better than good projector beam halogens.

wow....holy old thread batman.

I remember the HID scare back in 02......the good ol days

HID's on some cars give it that "evil" look or "shark" look like the S2000. Its the SUV's with HID's that are annoying....

I've been blinded by people that have their High Beams on but HID lights c'mon. Other note though I've been blinded by the Bobs back door HID bulbs known to be found in hondas.

Screw all this HID stuff. I want night vision, radar and sonar that sees out a mile or more and over hills and around curves and behind and to both sides etc and doesn't blind other drivers. Give me some of that secret stuff they used in Afghanistan. Satellite uplink to something that that has everthing below identified...............my own set of drones... lasers that zap deer and dogs when they cross the road in front of my car.
:lol: :lol: :lol: :lol:

I hope they get banned or at least changed over to "high beam" type where you kill them as a courtesy to oncomming traffic...

HID = My safety is more important than yours = I am more important than you

that is why BMWs have them ;) because they are for people that like to pretend they are more important than everyone else.

Well.....just to chime in for the hell of it.....

I love the HID's on my STi. I also love the fact that I can turn the little dial and point them much more at the ground. I rarely drive in pitch-black dark-of-night, but when I do, I'm usually on reasonably lit streets or highways.

Most of the time when my headlights are on, it is more to be seen than it is to allow me to see. In those instances, I always dial my HID headlights to point down (#3 on the dial) as I am acutely aware of how blinding they can be to other drivers.

I remember back when I had my previous car, just before I sold it. I was driving home and had just pulled into my neighborhood. It was pretty dark, and all I had was the regular old halogen low-beams. A Lexus RS330 SUV was behind me, and I remember just cursing non-stop at how damn bright his lights were, right at eye level (my old car was an Eagle Talon, very low to the ground) and blinding even with the rear view mirror "dimmed".

Then they turned off into their driveway, and I was absolutely astonished at how much darker everything in front of me got. His lights were *so* bright that they were actually overpowering my headlights even though he was behind me. Absolutely amazing.

Are HID's brighter and produce way more light? Hell YES! Do they produce a lot of glare that is blinding in oncoming traffic? Not really if properly installed. I've noticed that at night on my way home, I can spot the HID-equipped cars on the westbound lanes of the divided 4-lane road I'm on due to the color differences. They aren't tossing out a lot of glare. But they are brighter right at the headlight...more of a bright point of light than the standard halogens.

Just my $0.02.

-Michael

And as far as the aftermarket kits go they are already illegal and explicitly state they are for offroad use only.




gee do ya think? this thread is only 4 years old....

The NHTSA did officially ban the sale of aftermarket HID retrofits in August 03 following years of complaints. While the kits had always been technically illegal and for "off road use only" they were still being sold openly without penalty, and the govt made it clear that this was no longer to be the case. This is why since that time you don't see any of the well-known vendors carrying HIDs any more, just the smaller fly-by-night ones, and why it's "buyer beware" more than ever for anyone who still insists on buying these kits.
There has been some talk lately of the ban being relaxed, there is a fairly recent thread in this forum on the subject, but as of now nothing has changed.

And from my experience they are the ones always driving with their highbeams on. I would say this is more of a problem.....


Hey if the light bothers geezers that much they shouldn't be driving at night anyway. :devil:

Ehh they could ban em, they aren't really any better than good projector beam halogens.

Ummm strongly disagree on that one. Just look at the stats. They have about twice the lumens, require less power once ignited and dont flicker whenever your car's fan starts. And as far as projectors go I believe reflectors are more efficient at gathering all the light scattered in every direction, which is something projectors neverd did.

Also if halogens are so good how come most ppl want HIDs?

gee do ya think? this thread is only 4 years old....

yep...its old and it keeps coming back...

Also if halogens are so good how come most ppl want HIDs?
they're "in" and "sexy" and "cooler looking"

people wanting something is not necessarily proof they're better.

And you can put out all the lumens you want, certain types of lighting better lend themselves to human vision than others and there's plenty of arguments against HIDs.

I always dial my HID headlights to point down (#3 on the dial) as I am acutely aware of how blinding they can be to other drivers.

Yes, I am also very acutely aware...but mine is always dialed to 0! :banana:
If I could, I would set it to -10; that should be enough to get all those SUV and truck driving bastards back! But frankly I just dont care. My eyes have long ago mutated to enjoy and linger in HID light. Its those unsightly yellow halogens that make everything around them ugly and ruin all the fun! :D

Doesn't 'blue' light increase contrast?

Someone noted that they can see better when someone with HID is driving behind them, overpowering their lights, and I completely agree. Halogens are certainly far better than they used to be, but they still 'pale' (*snicker*) in comparison to HIDs, IMHO.

The key, as with all things, is control and moderation: The fastest drivers aren't those who press the pedal hardest, it's those who have the best control. The best lights are those that are designed for the application. You can't tell me that the Projector housing, cutoff shield, blub, etc. are designed any differently for a BMW X-5, Lexus RX330, or S2000, and therein lies the problem. Cost prohibitave? Yes. Necessary? No. But it would reduce a lof of the complaints, I assure you.

While this is NOT just a California thing, in my experience, California is the worst-case scenario for laws, regulations, and restrictions.

From California Vehicle Code, Division 12, Chapter 2, Article 2, Section 24400:
"(a) During darkness and inclement weather, a motor vehicle, other than a motorcycle, shall be equipped with at least two lighted headlamps, with at least one on each side of the front of the vehicle, and, except as to vehicles registered prior to January 1, 1930, they shall be located directly above or in advance of the front axle of the vehicle. The headlamps and every light source in any headlamp unit shall be located at a height of not more than 54 inches nor less than 22 inches."

I think that's too broad a range, especially since there are a vast majority of vehicles that can limbo under 54" all day long, and that's just asking for blinding light in someone's rear-view.

As far as head on, there are instances where there is little separation between lanes on say a freeway, where the 'median' is at most 6' wide, and the dividing element is not sufficiently high enough to block or diffuse light coming from the other direction, and THAT is the only time that any light bugs me, other than shining into my eyes from behind me via the rear-view mirrors (and you can't 'dim' the side mirrors :rolleyes: ) and it has no bearing on HID or non-HID, it's just glare.

IMHO, there are lots of areas that are well enough lit most of the time to be able to drive without lights at all, save, maybe 'parking' lights. You don't need ump-teen gazillion candela to light up the bumper of the car in front of you in bumper-to bumper traffic at night, or in the mall parking lot, etc. It's when you get out in the open, and there are no street lights, no moon, and you're lucky if there's reflectors (or a road :huh: ) that you need all that light. But having it, makes all the difference in the world.

When you get into pitch black conditions on an open road, you don't always want more light. The more light you have right in front of you, the more yor pupil will contract and the less your view into the longer distance is. It's easier to miss the dark spot ahead that's a pothole or tire strip on the road, or the glint of an animal's eye untill it's too late to avoid it. As Stern's site mentions, "closer to daylight" is not what you want to have when you have at night, at least if you are going over 50 mph and are not on a closed rally course.

For inclimate weather, HIDs scatter and dazzle a lot more than halogen, just like when you put on your high beams. Again, I think Stern's site covers this better than I can describe in a sentence. Driving home from Denver last week I ended up in a miserable fog bank that lasted the whole of Iowa. Any cars with HIDs were a menace to have nearby; they threw out way too much light everywhere.

Kevin, you've hit on what should be obvious, but escapes many people: It's not that HID headlamps are better than halogen ones. It's that good headlamps are better than bad headlamps. REGARDLESS of what light source is used in them!


Amen! I used to drive an '03 EVO, which came with HIDs standard. They sucked. While they looked cool, the aiming from the factory still gave me very limited visible distance (even at the highest setting on the leveling mechanism). I traded in the EVO and now drive a Mazda 3s 5-door. It has halogen lamps in a projector housing, and visibility is WAY better than my EVO was. It's like night and day (literally!).


Cabo

it's sad reading all the misconceptions that people STILL have in this recent flurry of bumping this 4 year old thread...

go read http://www.danielsternlighting.com/tech/bulbs/blue/blue.html and then reconsider your comments.

Summary: HID lights are worse than halogens in every meaningful measurement except power consumption.