HID Xeon Headlights
02-23-2003, 06:24 PM
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HID Xenon Headlights
I have seen dozens of RX-8 pics, but I've never seen a pic of the HID's. All pics with the headlights on look like standard halogens behind the projector. Has anyone seen the Xeon's?
Last edited by Gyro; 02-23-2003 at 11:23 PM.
02-23-2003, 06:40 PM
#2
Prodigal Wankler
Re: HID Xeon Headlights
Originally posted by Gyro
Has anyone seen the Xeon's?
Has anyone seen the Xeon's?
02-23-2003, 10:44 PM
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DrKill.....do those really look like HID's....not to me. the light should look dramatically whiter than the fog lights. this 350z pic looks more like it.
02-24-2003, 12:53 AM
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the headlamps are probably designed specifically for HID lights... but why would you go to the cost of putting HID's in show cars that aren't gonna get driven?? they're like $2k a pop, right?? you don't need to have HID's in your showcar to demonstrate that the glass in the lamps is clear...
no worries, i'm sure it'll look just as you imagine it (just like that, but whiter and blindingly brighter)
no worries, i'm sure it'll look just as you imagine it (just like that, but whiter and blindingly brighter)
Maybe a little
02-26-2003, 08:14 PM
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Last edited by P00Man; 04-16-2011 at 04:46 PM.
02-27-2003, 07:22 AM
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I don't really understand what's the big deal with HID or xenons. I bought a set of high wattage (110w vs 55w), superwhite PIAAs and they are pretty nice. The set cost about $50 and compared to a $500+ HID system, I very happy with the results.
Is there a difference is brightness? I know HID use a lot less electricity, but I don't really see why that matters in a car.
Is there a difference is brightness? I know HID use a lot less electricity, but I don't really see why that matters in a car.
02-27-2003, 11:24 AM
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HID are an intensely bright light, about 4 or so times brighter than standard halogen bulbs. The halogens burn at about 3000 degress where as xenons burn at 5000-5500
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Last edited by P00Man; 04-16-2011 at 04:48 PM.
02-27-2003, 11:29 AM
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Originally posted by max_stirling
I don't really understand what's the big deal with HID or xenons. I bought a set of high wattage (110w vs 55w), superwhite PIAAs and they are pretty nice. The set cost about $50 and compared to a $500+ HID system, I very happy with the results.
Is there a difference is brightness? I know HID use a lot less electricity, but I don't really see why that matters in a car.
I don't really understand what's the big deal with HID or xenons. I bought a set of high wattage (110w vs 55w), superwhite PIAAs and they are pretty nice. The set cost about $50 and compared to a $500+ HID system, I very happy with the results.
Is there a difference is brightness? I know HID use a lot less electricity, but I don't really see why that matters in a car.
The PIAA 55w version bulbs are plenty white and meet the legal limit for brightness. HIDs save you a no more than what amounts to a tenth of a horsepower (and any additional weight of an HID system offsets any horsepower it frees up)
-Mr. Wigggles
02-27-2003, 12:19 PM
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but HID's do give you brighter light, up to 400% more intense in the concentrated areas... it's just a matter of improvement: the way our economy works... why have something that's inferior??
granted, yes, the production cost of xenon lights is still very high, but someday most cars will have HIDs, presumably.
... another big benefit of having HIDs from a drivers point of view isn't that the lights are brighter, but that there are regulations in place to control that much brighter light... i've never had anything blind me better than some idiot kid in a Civic/Prelude with CoolBlue headlights... and strangely enough, (i find) i can almost look right at oncoming BMW's, Audi's, Lexuses with HID packages and not get too blinded...
granted, yes, the production cost of xenon lights is still very high, but someday most cars will have HIDs, presumably.
... another big benefit of having HIDs from a drivers point of view isn't that the lights are brighter, but that there are regulations in place to control that much brighter light... i've never had anything blind me better than some idiot kid in a Civic/Prelude with CoolBlue headlights... and strangely enough, (i find) i can almost look right at oncoming BMW's, Audi's, Lexuses with HID packages and not get too blinded...
02-27-2003, 02:10 PM
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European cars with HIDS (and Lexii too) have self leveling headlights (legal requirement in Europe I believe) as otherwise people could be blinded when on a slope (why doesn't the US have useful laws like this). When I start my IS300 the (standard) HIDS go through a leveling test (up, down, level) which looks cool.
02-27-2003, 02:44 PM
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from the NHTSA archives
"Educated and knowledgeable" statements by the NHTSA about HIDs and other types of illumination.
2.2 - Glare from High Intensity Discharge Headlamps
In the case of HIDs, we have received numerous complaints stating that these newer lamps produce excessive glare. Even though they are required to comply with all federal lighting requirements and we have no reason to believe that they do not comply, HIDs are still being singled out as being troublesome glare producers for other drivers. The reason expressed by drivers is that the HID headlamps are brighter. This may be due to the spectral content of the produced light, the generally wider and more robust beam pattern, and/or their conspicuous color relative to other headlamps, or misaim.
In an effort to create a headlamp which provides better illumination, longer life, and a unique styling appearance, vehicle lighting manufacturers developed HIDs. They have been typically offered on higher end vehicles and can cost as much a $400 to $800 for the option. HIDs are unlike conventional halogen headlamps in that they operate more like street lamps. Instead of heating a tungsten filament, an electrical arc is created between two electrodes. This excites a gas inside the headlamp (usually xenon) which in turn vaporizes metallic salts. These vaporized metallic salts sustain the arc and emit the light used for the headlamp's beam. These lamps provide more light than that produced by halogen lamps and only use two-thirds the power. As a result, they are more efficient, and because there is no filament to burn out, these bulbs are claimed to last for as much as 100,000 miles of driving time.
Although the agency has seen advertising and received many complaints claiming that the light produced by HIDs is twice or three times as bright as that which is produced by halogen lamps, laboratory measurement, made by various parties, do not support these claims. HID light sources (bulbs) typically have about two to three times the available light flux (volume) of halogen light sources, but because of such an abundance of light, the HID optical design does not necessarily need to be as efficient at collecting and distributing light as a halogen system. The HID beam pattern is certainly more robust, providing more even and wider illumination and the potential for better visibility and comfort. This performance results in more light on the road surface and more of the roadway being illuminated. However, this additional light is not supposed to be projected upward from the lamp toward other drivers' eyes. During inclement weather, when the road surface is wet, the additional volume of light can result in higher levels of light reflected off the road surface into other drivers' eyes. However, those who have complained about HID glare have not specifically reported inclement weather as the only time when there is a problem with HID glare.
Another factor that may be involved is the phenomenon that may have occurred with the introduction of halogen lamps in the early 1980's. Drivers are attracted to headlamps that are different colors than would normally be seen. As such, the drivers may look directly at oncoming headlamps during driving to see the unfamiliar item. This is something that they do not normally do. Initial halogen headlamp introduction elicited some glare complaints, even though the first halogens used were actually very similar in performance to the standard non-halogens headlamps. The only marked difference was the color of the halogen headlamps. If this is the case now, one would expect glare complaints about HIDs to stop when drivers become familiar with the HID color. NHTSA is aware of no studies or evidence to suggest that this theory is correct.
Another factor that may lead to the perception that HIDs are significantly brighter than halogen lamps is that human eyes may be more sensitive to bluish-white light of HIDs than to yellowish-white light of halogens. When observing some HIDs, it may seem that they are not emitting white light, as required by Standard No. 108. However, when observing the beam pattern projected on a white screen, HID headlamps that comply with our lighting standard will appear to be white with color separations occurring only at the extreme edges of the pattern. Non-halogen, halogen, and HID light sources appear to be different colors to observers. Non-halogen lamps appear to be yellow when compared to halogen lamps, and halogen lamps appear to be yellow when compared to HIDs.
In a recent study by the University of Michigan Transportation Research Institute (Flannagan, M. J.; 1999, ASubjective and Objective Aspects of Headlamp Glare: Effects of Size and Spectral Power Distribution," Report No. UMTRI-99-36, available in Docket Number: NHTSA-2001-8885-3) the differences reported between halogen versus HID lamps caused a small but statistically significant difference in discomfort glare noted by observers. However, it had no effect on disability glare. It is not known yet whether it is the difference in spectral power density of these headlamps, but this difference in the human eye's glare response to these different lamp designs is shown in that study.
HIDs are not just more white (having less yellow content and more blue content in the emitted spectrum), but the light is generated in a different manner. HIDs achieve light by having vaporized metallic salts participate in the electrical current flow through an arc in the bulb capsule. This is contrasted to a heated metal filament which gives a relatively even level of light at all colors in the spectrum, and thus achieves smoother white light. The HIDs blend of metallic salts is designed such that the different salts, emitting different colors of light with different energy levels, will complement each other when fully heated and electricity is passed through them, because each salt contributes various frequencies of light and at different levels of energy. The result is white light, but with a few relatively high energy spikes of light at very narrow bandwidths. These spikes are obvious in a mapping of the spectral power density of the light emitted. (See Docket Number: NHTSA-2001-8885-4, USA Today, June 7, 2001, "Bright Lights, Big Controversy" by James R. Healey, page 1, the side bar Aharsh blue light contributes to glare"). This comparison shows that the light spectrum of HIDs is not as smooth as the light from a heated filament in a halogen lamp. It is possible that our eyes are not necessarily reacting to the whiter light, but to the high energy spikes that rise above a background energy achieving the white light. If this is a cause for the UMTRI findings, it may be that a redesign of the HID system is necessary. However, this is just a theory, with no supporting data. NHTSA is initiating research to study all potential factors that may be causing HIDs to be an annoying lighting source.
2.3 - Glare from HID Look-alike Bulbs and Other Colored Headlamp Bulbs
The advent of HIDs on more expensive vehicles has spawned attempts at achieving halogen-based look-a-likes. These are achieved by using coated, tinted, filtered or otherwise altered glass capsules for the halogen headlamp bulbs that can be used in place of the OEM bulbs. Alternatively, aftermarket headlamp housings with similar coating, tinting and filtering are being sold as replacements for OEM headlamps. The goal of many of these bulbs is to emit light that is different than an OEM halogen headlamp bulb, while attempting to maintain a headlamp's legally complying performance. The whiter light is offered as being closer in color to natural daylight, thus the claim is that drivers see better with the same amount of emitted light. This is not unique in motor vehicle lighting history; in fact, it is the same claim and intent as accompanied the 1929 Tung-Sol Blue-Wite TM headlamp bulb. The yellow variants of colored bulbs are intended to be more useful in wet weather where the color, still measured to be white, is more yellow than OEM halogen bulbs. The intent is to offer a color of light less likely to be reflected back from precipitation and fog. At the other extreme of colored aftermarket bulbs, are those that are very blue or multicolored. The multicolored bulbs are the result of many different colors being emitted by the bulb in various directions, instead of white light being emitted in all directions as occurs in normal halogen bulbs.
Generically categorized as "blue" bulbs, all of these aftermarket bulbs have become popular among auto enthusiasts and some other drivers, either because the bulbs produce the look of a more expensive vehicle at a fraction of the cost, or claims of improved visibility. Many of the bulbs are from well known bulb manufacturers, others are from less familiar companies and importers. Depending on the make and model of bulb desired, some are sold by auto parts stores and mass merchandisers, others are sold by specialty auto accessory stores and through the Internet. While there are no reasons to believe that all such bulbs cause headlamps to perform badly, many such bulbs do just that, as explained below.
The designing original equipment headlamp bulbs is a precise science, fraught with many design compromises in order to achieve the desired balance of energy usage, service life, emitted light and robust optical images of the filament. In general, headlamp bulb designs take years of thoughtful work in consultation with the designers of headlamp optics. The OEM bulb design is standardized and codified by industry consensus in SAE and International Electrotechnical Committee (IEC) standards so that all bulb manufacturers can build and sell bulbs with the expectation that they will perform in a safe and satisfactory manner in all headlamps in service. This standardization is incorporated into Federal Motor Vehicle Safety Standard No. 108, Lamps, reflective devices and associated equipment (FMVSS 108) by referencing information about each bulb. This information is in Docket Number: NHTSA-98-3397.
When changing the basic design of a headlamp bulb the way that placing a coating, filter or tinting can, the results can range from just color changes to reducing the emitted volume of light from a headlamp by almost half. For example, certain kinds of filters and coatings, while having the effect of reducing yellow light emission, are sometimes also very reflective. The result is that, instead of most of the light coming from the filament directly through the glass capsule and being used by the headlamp's optical design to have a focused beam down the road, the light bounces once or twice off the inner wall of the bulb. This causes strong images of the filament to be emitted from the capsule in directions and intensities never possible in the standardized OEM design. Because headlamps are designed to use standardized bulbs, the lighting performance of the headlamp could be markedly different, both impairing seeing down the road and causing others to have undue glare, when a modified, non-standardized bulb is substituted. Such poorly designed bulbs may also be a reason for the public's glare complaints.
In contrast, if the bulb designer uses a more benign filter element, the inner bulb reflectivity may be substantially reduced or virtually eliminated. For a bulb that is intended to be whiter, less yellow light may be emitted, giving the light a whiter, even bluish light, but still white light as defined in various industrial and legal standards. To assure that this bulb emits the equivalent and correct volume of light compared to an OEM version, the filament design must be subtly changed, but not so much so that wattage increases above the acceptable limits required of a standard bulb. These careful changes may continue to make the bulb interchangeable with an OEM design without noticeable consequence other than whiter light.
Besides replacing the OEM bulbs with bulbs with the characteristics described above, it is possible to purchase whole headlamps and replacement lenses for those that are replaceable, that are tinted. Under our standards, these must comply, with our lighting standard but again, the blue, or other color, tinting may have similar adverse disturbing and disabling glare effects .
Another disturbing trend in this look-a-like phenomenon is the substitution of OEM filament headlamp bulbs with aftermarket HID conversion bulbs. The desire is to achieve the look and achieve the more robust performance of HIDs. While not designed to be interchangeable, some aftermarket companies are substantially altering the HID bulb bases or providing adapters so that the HID bulbs can be inserted in headlamps designed for filament bulbs. The consequence of making these substitutions is to adversely affect safety. Filament headlamps are optically designed for the volume of light and filament placement and other critical dimensions and performance that OEM filament bulbs have. The HID conversions result in two to three times the volume of light and potentially imprecise arc placement. Such conversions often result in beam patterns that behave nothing like the original filament beam pattern, cannot be reliably aimed, and have many times the permitted glare intensity. In informal conversations with persons who have tested such conversions, the light intensity on one at a point aimed toward oncoming drivers was 22 times the allowable intensity limit. Another lamp was more than 7 times too intense. With poor HID bulb and arc placement, the glare intensity could be significantly worse. Thus, the use of these conversions could be yet another source of the glare problems about which many drivers have complained.
Regarding bluer light achieved by these filament bulbs, recent research (Sullivan, J.M. and Flannagan, M.J.: AVisual Effects of Blue-Tinted Tungsten-Halogen Headlamp Bulbs", Report No. UMTRI-2001-9, available in Docket: NHTSA-2001-8885-2) shows consistency with prior research, that discomfort glare ratings increase as the chromaticity moves toward the blue color range of the visible light spectrum. The authors also state that there is no evidence to show that target detection is enhanced with such blue colored headlamps, either in direct viewing or peripheral viewing of illuminated targets. This, essentially, shows that there likely is an inherent disbenefit from the use of such blue bulbs and headlamps that are intended to change the color of light emitted from headlamps. While one might assume that this also applies to the bluer HID powered OEM headlamps, the authors did not study this, nor speculate about it.
2.4 - Glare from Fog Lamps, Driving Lamps, and Auxiliary Low Beam Headlamps
Fog lamps, driving lamps, and auxiliary low beam headlamps are lamps used in addition to the normally required headlamps. These lamps have been identified in state laws for decades as being allowed to be used under certain conditions of visibility. Generally, as defined in SAE standards, fog lamps have a wide even beam, less intense than a low beam, and intended to be mounted low to shine out under blankets of fog hovering near the ground, and in other conditions of reduced visibility such as rain, snow and dust. Properly aimed, fog lamps can be used to reduce the back scatter glare that often results from water droplets, snowflakes and dust particles illuminated by headlamps. The fog lamp with its downward aimed beam can reduce that veiling glare and permit seeing, albeit at much shorter distance, the roadway and important targets. Speeds, of course, have to be reduced under those conditions.
Driving lamps are lamps not intended for general driving, but are intended to supplement the upper beam headlamps. In essence, they are auxiliary upper beam headlamps. As such, they should never be used under conditions that do not permit the use of upper beam headlamps. Their beam intensity and aim are described in SAE standards and often referenced in state motor vehicle law.
The Auxiliary Low Beam Headlamp, is just that, a lamp similar in beam pattern and performance to a lower beam headlamp. It is intended to supplement the lower beam headlamp, more typically for turnpike driving, where the roadway has widely separated opposing lanes.
More and more passenger cars and LTVs are being equipped with auxiliary lamps these days. As an OEM option, the lamps, usually fog lamps, offer different styling cues than the normal model vehicle to help differentiate it in the market. Also, the public may be interested in "better" lighting, because the number of both OEM and aftermarket installations is increasing markedly. Because of fog lamps' limited performance, they by design will not markedly improve seeing under normal conditions.
These auxiliary lamps are now becoming a source of complaint for glare. Often described as another set of headlamps, sometimes mounted lower, the public reports that these lamps seem to be used all the time at night. In fact, research has now documented that the public is right. Sivak et. al. reported that fog lamps were in fact used much more often than was appropriate for the conditions. In fact, most of the auxiliary lamps in the census were on regardless of the weather or visibility conditions, and most vehicles that had them installed had them in use (see Sivak, M.; Flannagan, M. J.; Traube, E. C.; Hashimoto, H.; Kojima, S. 1997, "Fog lamps: Frequency of Installation and Nature of Use," No. UMTRI-96-31, available as Docket NHTSA-1998-8885-1).
This documented misuse of fog lamps in particular helps substantiate the complaints that NHTSA has been receiving. NHTSA has had complaints about fog lamp use for a while, but never so many as recently. As part of another rulemaking (63 FR 68233, December 12, 1998), NHTSA asked whether it should regulate fog lamps in general, because it was petitioned to regulate the geometric visibility of fog lamps as installed on motor vehicles. The response by commenters to this question was unanimous: yes, please regulate them. NHTSA's authority to regulate their safety will have the consequence of having a common national standard for them. Some of the commenters suggested waiting until the SAE and other international organizations achieved a harmonized, but updated version of a fog lamp standard. As a result of that request, NHTSA has been waiting several years for this to occur. However, there appears to be significant disagreement within both the SAE's Lighting Committee and the Groupe de Travail Brusselles, 1958 , (GTB) as to what constitutes the current state of industry performance for fog lamps. For the foreseeable future, NHTSA has no expectation that a harmonized fog lamp performance consensus standard will be forthcoming from SAE or GTB. Because of the significant increase in complaints, NHTSA plans to propose action independently of outdated industry standards for fog, auxiliary and driving lamps to regulate these at the federal level.
2.2 - Glare from High Intensity Discharge Headlamps
In the case of HIDs, we have received numerous complaints stating that these newer lamps produce excessive glare. Even though they are required to comply with all federal lighting requirements and we have no reason to believe that they do not comply, HIDs are still being singled out as being troublesome glare producers for other drivers. The reason expressed by drivers is that the HID headlamps are brighter. This may be due to the spectral content of the produced light, the generally wider and more robust beam pattern, and/or their conspicuous color relative to other headlamps, or misaim.
In an effort to create a headlamp which provides better illumination, longer life, and a unique styling appearance, vehicle lighting manufacturers developed HIDs. They have been typically offered on higher end vehicles and can cost as much a $400 to $800 for the option. HIDs are unlike conventional halogen headlamps in that they operate more like street lamps. Instead of heating a tungsten filament, an electrical arc is created between two electrodes. This excites a gas inside the headlamp (usually xenon) which in turn vaporizes metallic salts. These vaporized metallic salts sustain the arc and emit the light used for the headlamp's beam. These lamps provide more light than that produced by halogen lamps and only use two-thirds the power. As a result, they are more efficient, and because there is no filament to burn out, these bulbs are claimed to last for as much as 100,000 miles of driving time.
Although the agency has seen advertising and received many complaints claiming that the light produced by HIDs is twice or three times as bright as that which is produced by halogen lamps, laboratory measurement, made by various parties, do not support these claims. HID light sources (bulbs) typically have about two to three times the available light flux (volume) of halogen light sources, but because of such an abundance of light, the HID optical design does not necessarily need to be as efficient at collecting and distributing light as a halogen system. The HID beam pattern is certainly more robust, providing more even and wider illumination and the potential for better visibility and comfort. This performance results in more light on the road surface and more of the roadway being illuminated. However, this additional light is not supposed to be projected upward from the lamp toward other drivers' eyes. During inclement weather, when the road surface is wet, the additional volume of light can result in higher levels of light reflected off the road surface into other drivers' eyes. However, those who have complained about HID glare have not specifically reported inclement weather as the only time when there is a problem with HID glare.
Another factor that may be involved is the phenomenon that may have occurred with the introduction of halogen lamps in the early 1980's. Drivers are attracted to headlamps that are different colors than would normally be seen. As such, the drivers may look directly at oncoming headlamps during driving to see the unfamiliar item. This is something that they do not normally do. Initial halogen headlamp introduction elicited some glare complaints, even though the first halogens used were actually very similar in performance to the standard non-halogens headlamps. The only marked difference was the color of the halogen headlamps. If this is the case now, one would expect glare complaints about HIDs to stop when drivers become familiar with the HID color. NHTSA is aware of no studies or evidence to suggest that this theory is correct.
Another factor that may lead to the perception that HIDs are significantly brighter than halogen lamps is that human eyes may be more sensitive to bluish-white light of HIDs than to yellowish-white light of halogens. When observing some HIDs, it may seem that they are not emitting white light, as required by Standard No. 108. However, when observing the beam pattern projected on a white screen, HID headlamps that comply with our lighting standard will appear to be white with color separations occurring only at the extreme edges of the pattern. Non-halogen, halogen, and HID light sources appear to be different colors to observers. Non-halogen lamps appear to be yellow when compared to halogen lamps, and halogen lamps appear to be yellow when compared to HIDs.
In a recent study by the University of Michigan Transportation Research Institute (Flannagan, M. J.; 1999, ASubjective and Objective Aspects of Headlamp Glare: Effects of Size and Spectral Power Distribution," Report No. UMTRI-99-36, available in Docket Number: NHTSA-2001-8885-3) the differences reported between halogen versus HID lamps caused a small but statistically significant difference in discomfort glare noted by observers. However, it had no effect on disability glare. It is not known yet whether it is the difference in spectral power density of these headlamps, but this difference in the human eye's glare response to these different lamp designs is shown in that study.
HIDs are not just more white (having less yellow content and more blue content in the emitted spectrum), but the light is generated in a different manner. HIDs achieve light by having vaporized metallic salts participate in the electrical current flow through an arc in the bulb capsule. This is contrasted to a heated metal filament which gives a relatively even level of light at all colors in the spectrum, and thus achieves smoother white light. The HIDs blend of metallic salts is designed such that the different salts, emitting different colors of light with different energy levels, will complement each other when fully heated and electricity is passed through them, because each salt contributes various frequencies of light and at different levels of energy. The result is white light, but with a few relatively high energy spikes of light at very narrow bandwidths. These spikes are obvious in a mapping of the spectral power density of the light emitted. (See Docket Number: NHTSA-2001-8885-4, USA Today, June 7, 2001, "Bright Lights, Big Controversy" by James R. Healey, page 1, the side bar Aharsh blue light contributes to glare"). This comparison shows that the light spectrum of HIDs is not as smooth as the light from a heated filament in a halogen lamp. It is possible that our eyes are not necessarily reacting to the whiter light, but to the high energy spikes that rise above a background energy achieving the white light. If this is a cause for the UMTRI findings, it may be that a redesign of the HID system is necessary. However, this is just a theory, with no supporting data. NHTSA is initiating research to study all potential factors that may be causing HIDs to be an annoying lighting source.
2.3 - Glare from HID Look-alike Bulbs and Other Colored Headlamp Bulbs
The advent of HIDs on more expensive vehicles has spawned attempts at achieving halogen-based look-a-likes. These are achieved by using coated, tinted, filtered or otherwise altered glass capsules for the halogen headlamp bulbs that can be used in place of the OEM bulbs. Alternatively, aftermarket headlamp housings with similar coating, tinting and filtering are being sold as replacements for OEM headlamps. The goal of many of these bulbs is to emit light that is different than an OEM halogen headlamp bulb, while attempting to maintain a headlamp's legally complying performance. The whiter light is offered as being closer in color to natural daylight, thus the claim is that drivers see better with the same amount of emitted light. This is not unique in motor vehicle lighting history; in fact, it is the same claim and intent as accompanied the 1929 Tung-Sol Blue-Wite TM headlamp bulb. The yellow variants of colored bulbs are intended to be more useful in wet weather where the color, still measured to be white, is more yellow than OEM halogen bulbs. The intent is to offer a color of light less likely to be reflected back from precipitation and fog. At the other extreme of colored aftermarket bulbs, are those that are very blue or multicolored. The multicolored bulbs are the result of many different colors being emitted by the bulb in various directions, instead of white light being emitted in all directions as occurs in normal halogen bulbs.
Generically categorized as "blue" bulbs, all of these aftermarket bulbs have become popular among auto enthusiasts and some other drivers, either because the bulbs produce the look of a more expensive vehicle at a fraction of the cost, or claims of improved visibility. Many of the bulbs are from well known bulb manufacturers, others are from less familiar companies and importers. Depending on the make and model of bulb desired, some are sold by auto parts stores and mass merchandisers, others are sold by specialty auto accessory stores and through the Internet. While there are no reasons to believe that all such bulbs cause headlamps to perform badly, many such bulbs do just that, as explained below.
The designing original equipment headlamp bulbs is a precise science, fraught with many design compromises in order to achieve the desired balance of energy usage, service life, emitted light and robust optical images of the filament. In general, headlamp bulb designs take years of thoughtful work in consultation with the designers of headlamp optics. The OEM bulb design is standardized and codified by industry consensus in SAE and International Electrotechnical Committee (IEC) standards so that all bulb manufacturers can build and sell bulbs with the expectation that they will perform in a safe and satisfactory manner in all headlamps in service. This standardization is incorporated into Federal Motor Vehicle Safety Standard No. 108, Lamps, reflective devices and associated equipment (FMVSS 108) by referencing information about each bulb. This information is in Docket Number: NHTSA-98-3397.
When changing the basic design of a headlamp bulb the way that placing a coating, filter or tinting can, the results can range from just color changes to reducing the emitted volume of light from a headlamp by almost half. For example, certain kinds of filters and coatings, while having the effect of reducing yellow light emission, are sometimes also very reflective. The result is that, instead of most of the light coming from the filament directly through the glass capsule and being used by the headlamp's optical design to have a focused beam down the road, the light bounces once or twice off the inner wall of the bulb. This causes strong images of the filament to be emitted from the capsule in directions and intensities never possible in the standardized OEM design. Because headlamps are designed to use standardized bulbs, the lighting performance of the headlamp could be markedly different, both impairing seeing down the road and causing others to have undue glare, when a modified, non-standardized bulb is substituted. Such poorly designed bulbs may also be a reason for the public's glare complaints.
In contrast, if the bulb designer uses a more benign filter element, the inner bulb reflectivity may be substantially reduced or virtually eliminated. For a bulb that is intended to be whiter, less yellow light may be emitted, giving the light a whiter, even bluish light, but still white light as defined in various industrial and legal standards. To assure that this bulb emits the equivalent and correct volume of light compared to an OEM version, the filament design must be subtly changed, but not so much so that wattage increases above the acceptable limits required of a standard bulb. These careful changes may continue to make the bulb interchangeable with an OEM design without noticeable consequence other than whiter light.
Besides replacing the OEM bulbs with bulbs with the characteristics described above, it is possible to purchase whole headlamps and replacement lenses for those that are replaceable, that are tinted. Under our standards, these must comply, with our lighting standard but again, the blue, or other color, tinting may have similar adverse disturbing and disabling glare effects .
Another disturbing trend in this look-a-like phenomenon is the substitution of OEM filament headlamp bulbs with aftermarket HID conversion bulbs. The desire is to achieve the look and achieve the more robust performance of HIDs. While not designed to be interchangeable, some aftermarket companies are substantially altering the HID bulb bases or providing adapters so that the HID bulbs can be inserted in headlamps designed for filament bulbs. The consequence of making these substitutions is to adversely affect safety. Filament headlamps are optically designed for the volume of light and filament placement and other critical dimensions and performance that OEM filament bulbs have. The HID conversions result in two to three times the volume of light and potentially imprecise arc placement. Such conversions often result in beam patterns that behave nothing like the original filament beam pattern, cannot be reliably aimed, and have many times the permitted glare intensity. In informal conversations with persons who have tested such conversions, the light intensity on one at a point aimed toward oncoming drivers was 22 times the allowable intensity limit. Another lamp was more than 7 times too intense. With poor HID bulb and arc placement, the glare intensity could be significantly worse. Thus, the use of these conversions could be yet another source of the glare problems about which many drivers have complained.
Regarding bluer light achieved by these filament bulbs, recent research (Sullivan, J.M. and Flannagan, M.J.: AVisual Effects of Blue-Tinted Tungsten-Halogen Headlamp Bulbs", Report No. UMTRI-2001-9, available in Docket: NHTSA-2001-8885-2) shows consistency with prior research, that discomfort glare ratings increase as the chromaticity moves toward the blue color range of the visible light spectrum. The authors also state that there is no evidence to show that target detection is enhanced with such blue colored headlamps, either in direct viewing or peripheral viewing of illuminated targets. This, essentially, shows that there likely is an inherent disbenefit from the use of such blue bulbs and headlamps that are intended to change the color of light emitted from headlamps. While one might assume that this also applies to the bluer HID powered OEM headlamps, the authors did not study this, nor speculate about it.
2.4 - Glare from Fog Lamps, Driving Lamps, and Auxiliary Low Beam Headlamps
Fog lamps, driving lamps, and auxiliary low beam headlamps are lamps used in addition to the normally required headlamps. These lamps have been identified in state laws for decades as being allowed to be used under certain conditions of visibility. Generally, as defined in SAE standards, fog lamps have a wide even beam, less intense than a low beam, and intended to be mounted low to shine out under blankets of fog hovering near the ground, and in other conditions of reduced visibility such as rain, snow and dust. Properly aimed, fog lamps can be used to reduce the back scatter glare that often results from water droplets, snowflakes and dust particles illuminated by headlamps. The fog lamp with its downward aimed beam can reduce that veiling glare and permit seeing, albeit at much shorter distance, the roadway and important targets. Speeds, of course, have to be reduced under those conditions.
Driving lamps are lamps not intended for general driving, but are intended to supplement the upper beam headlamps. In essence, they are auxiliary upper beam headlamps. As such, they should never be used under conditions that do not permit the use of upper beam headlamps. Their beam intensity and aim are described in SAE standards and often referenced in state motor vehicle law.
The Auxiliary Low Beam Headlamp, is just that, a lamp similar in beam pattern and performance to a lower beam headlamp. It is intended to supplement the lower beam headlamp, more typically for turnpike driving, where the roadway has widely separated opposing lanes.
More and more passenger cars and LTVs are being equipped with auxiliary lamps these days. As an OEM option, the lamps, usually fog lamps, offer different styling cues than the normal model vehicle to help differentiate it in the market. Also, the public may be interested in "better" lighting, because the number of both OEM and aftermarket installations is increasing markedly. Because of fog lamps' limited performance, they by design will not markedly improve seeing under normal conditions.
These auxiliary lamps are now becoming a source of complaint for glare. Often described as another set of headlamps, sometimes mounted lower, the public reports that these lamps seem to be used all the time at night. In fact, research has now documented that the public is right. Sivak et. al. reported that fog lamps were in fact used much more often than was appropriate for the conditions. In fact, most of the auxiliary lamps in the census were on regardless of the weather or visibility conditions, and most vehicles that had them installed had them in use (see Sivak, M.; Flannagan, M. J.; Traube, E. C.; Hashimoto, H.; Kojima, S. 1997, "Fog lamps: Frequency of Installation and Nature of Use," No. UMTRI-96-31, available as Docket NHTSA-1998-8885-1).
This documented misuse of fog lamps in particular helps substantiate the complaints that NHTSA has been receiving. NHTSA has had complaints about fog lamp use for a while, but never so many as recently. As part of another rulemaking (63 FR 68233, December 12, 1998), NHTSA asked whether it should regulate fog lamps in general, because it was petitioned to regulate the geometric visibility of fog lamps as installed on motor vehicles. The response by commenters to this question was unanimous: yes, please regulate them. NHTSA's authority to regulate their safety will have the consequence of having a common national standard for them. Some of the commenters suggested waiting until the SAE and other international organizations achieved a harmonized, but updated version of a fog lamp standard. As a result of that request, NHTSA has been waiting several years for this to occur. However, there appears to be significant disagreement within both the SAE's Lighting Committee and the Groupe de Travail Brusselles, 1958 , (GTB) as to what constitutes the current state of industry performance for fog lamps. For the foreseeable future, NHTSA has no expectation that a harmonized fog lamp performance consensus standard will be forthcoming from SAE or GTB. Because of the significant increase in complaints, NHTSA plans to propose action independently of outdated industry standards for fog, auxiliary and driving lamps to regulate these at the federal level.
OMG my head hurts. Thanks for the info.
02-27-2003, 02:53 PM
#17
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Recommended reading for all you web junkies out there.
http://dms.dot.gov/search/searchFormSimple.cfm
and search for this docket 8885
http://dms.dot.gov/search/searchFormSimple.cfm
and search for this docket 8885
02-28-2003, 12:27 AM
#18
Prodigal Wankler
Originally posted by MrWigggles
I agree 100%.
The PIAA 55w version bulbs are plenty white and meet the legal limit for brightness.
I agree 100%.
The PIAA 55w version bulbs are plenty white and meet the legal limit for brightness.
02-28-2003, 10:06 AM
#19
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Re: from the NHTSA archives
Originally posted by DrKillJoY
"Educated and knowledgeable" statements by the NHTSA about HIDs and other types of illumination.
2.2 - Glare from High Intensity Discharge Headlamps
In the case of HIDs, we have received numerous complaints stating that these newer lamps produce excessive glare. Even though they are required to comply with all federal lighting requirements and we have no reason to believe that they do not comply, HIDs are still being singled out as being troublesome glare producers for other drivers. The reason expressed by drivers is that the HID headlamps are brighter. This may be due to the spectral content of the produced light, the generally wider and more robust beam pattern, and/or their conspicuous color relative to other headlamps, or misaim.
In an effort to create a headlamp which provides better illumination, longer life, and a unique styling appearance, vehicle lighting manufacturers developed HIDs. They have been typically offered on higher end vehicles and can cost as much a $400 to $800 for the option. HIDs are unlike conventional halogen headlamps in that they operate more like street lamps. Instead of heating a tungsten filament, an electrical arc is created between two electrodes. This excites a gas inside the headlamp (usually xenon) which in turn vaporizes metallic salts. These vaporized metallic salts sustain the arc and emit the light used for the headlamp's beam. These lamps provide more light than that produced by halogen lamps and only use two-thirds the power. As a result, they are more efficient, and because there is no filament to burn out, these bulbs are claimed to last for as much as 100,000 miles of driving time.
Although the agency has seen advertising and received many complaints claiming that the light produced by HIDs is twice or three times as bright as that which is produced by halogen lamps, laboratory measurement, made by various parties, do not support these claims. HID light sources (bulbs) typically have about two to three times the available light flux (volume) of halogen light sources, but because of such an abundance of light, the HID optical design does not necessarily need to be as efficient at collecting and distributing light as a halogen system. The HID beam pattern is certainly more robust, providing more even and wider illumination and the potential for better visibility and comfort. This performance results in more light on the road surface and more of the roadway being illuminated. However, this additional light is not supposed to be projected upward from the lamp toward other drivers' eyes. During inclement weather, when the road surface is wet, the additional volume of light can result in higher levels of light reflected off the road surface into other drivers' eyes. However, those who have complained about HID glare have not specifically reported inclement weather as the only time when there is a problem with HID glare.
Another factor that may be involved is the phenomenon that may have occurred with the introduction of halogen lamps in the early 1980's. Drivers are attracted to headlamps that are different colors than would normally be seen. As such, the drivers may look directly at oncoming headlamps during driving to see the unfamiliar item. This is something that they do not normally do. Initial halogen headlamp introduction elicited some glare complaints, even though the first halogens used were actually very similar in performance to the standard non-halogens headlamps. The only marked difference was the color of the halogen headlamps. If this is the case now, one would expect glare complaints about HIDs to stop when drivers become familiar with the HID color. NHTSA is aware of no studies or evidence to suggest that this theory is correct.
Another factor that may lead to the perception that HIDs are significantly brighter than halogen lamps is that human eyes may be more sensitive to bluish-white light of HIDs than to yellowish-white light of halogens. When observing some HIDs, it may seem that they are not emitting white light, as required by Standard No. 108. However, when observing the beam pattern projected on a white screen, HID headlamps that comply with our lighting standard will appear to be white with color separations occurring only at the extreme edges of the pattern. Non-halogen, halogen, and HID light sources appear to be different colors to observers. Non-halogen lamps appear to be yellow when compared to halogen lamps, and halogen lamps appear to be yellow when compared to HIDs.
In a recent study by the University of Michigan Transportation Research Institute (Flannagan, M. J.; 1999, ASubjective and Objective Aspects of Headlamp Glare: Effects of Size and Spectral Power Distribution," Report No. UMTRI-99-36, available in Docket Number: NHTSA-2001-8885-3) the differences reported between halogen versus HID lamps caused a small but statistically significant difference in discomfort glare noted by observers. However, it had no effect on disability glare. It is not known yet whether it is the difference in spectral power density of these headlamps, but this difference in the human eye's glare response to these different lamp designs is shown in that study.
HIDs are not just more white (having less yellow content and more blue content in the emitted spectrum), but the light is generated in a different manner. HIDs achieve light by having vaporized metallic salts participate in the electrical current flow through an arc in the bulb capsule. This is contrasted to a heated metal filament which gives a relatively even level of light at all colors in the spectrum, and thus achieves smoother white light. The HIDs blend of metallic salts is designed such that the different salts, emitting different colors of light with different energy levels, will complement each other when fully heated and electricity is passed through them, because each salt contributes various frequencies of light and at different levels of energy. The result is white light, but with a few relatively high energy spikes of light at very narrow bandwidths. These spikes are obvious in a mapping of the spectral power density of the light emitted. (See Docket Number: NHTSA-2001-8885-4, USA Today, June 7, 2001, "Bright Lights, Big Controversy" by James R. Healey, page 1, the side bar Aharsh blue light contributes to glare"). This comparison shows that the light spectrum of HIDs is not as smooth as the light from a heated filament in a halogen lamp. It is possible that our eyes are not necessarily reacting to the whiter light, but to the high energy spikes that rise above a background energy achieving the white light. If this is a cause for the UMTRI findings, it may be that a redesign of the HID system is necessary. However, this is just a theory, with no supporting data. NHTSA is initiating research to study all potential factors that may be causing HIDs to be an annoying lighting source.
2.3 - Glare from HID Look-alike Bulbs and Other Colored Headlamp Bulbs
The advent of HIDs on more expensive vehicles has spawned attempts at achieving halogen-based look-a-likes. These are achieved by using coated, tinted, filtered or otherwise altered glass capsules for the halogen headlamp bulbs that can be used in place of the OEM bulbs. Alternatively, aftermarket headlamp housings with similar coating, tinting and filtering are being sold as replacements for OEM headlamps. The goal of many of these bulbs is to emit light that is different than an OEM halogen headlamp bulb, while attempting to maintain a headlamp's legally complying performance. The whiter light is offered as being closer in color to natural daylight, thus the claim is that drivers see better with the same amount of emitted light. This is not unique in motor vehicle lighting history; in fact, it is the same claim and intent as accompanied the 1929 Tung-Sol Blue-Wite TM headlamp bulb. The yellow variants of colored bulbs are intended to be more useful in wet weather where the color, still measured to be white, is more yellow than OEM halogen bulbs. The intent is to offer a color of light less likely to be reflected back from precipitation and fog. At the other extreme of colored aftermarket bulbs, are those that are very blue or multicolored. The multicolored bulbs are the result of many different colors being emitted by the bulb in various directions, instead of white light being emitted in all directions as occurs in normal halogen bulbs.
Generically categorized as "blue" bulbs, all of these aftermarket bulbs have become popular among auto enthusiasts and some other drivers, either because the bulbs produce the look of a more expensive vehicle at a fraction of the cost, or claims of improved visibility. Many of the bulbs are from well known bulb manufacturers, others are from less familiar companies and importers. Depending on the make and model of bulb desired, some are sold by auto parts stores and mass merchandisers, others are sold by specialty auto accessory stores and through the Internet. While there are no reasons to believe that all such bulbs cause headlamps to perform badly, many such bulbs do just that, as explained below.
The designing original equipment headlamp bulbs is a precise science, fraught with many design compromises in order to achieve the desired balance of energy usage, service life, emitted light and robust optical images of the filament. In general, headlamp bulb designs take years of thoughtful work in consultation with the designers of headlamp optics. The OEM bulb design is standardized and codified by industry consensus in SAE and International Electrotechnical Committee (IEC) standards so that all bulb manufacturers can build and sell bulbs with the expectation that they will perform in a safe and satisfactory manner in all headlamps in service. This standardization is incorporated into Federal Motor Vehicle Safety Standard No. 108, Lamps, reflective devices and associated equipment (FMVSS 108) by referencing information about each bulb. This information is in Docket Number: NHTSA-98-3397.
When changing the basic design of a headlamp bulb the way that placing a coating, filter or tinting can, the results can range from just color changes to reducing the emitted volume of light from a headlamp by almost half. For example, certain kinds of filters and coatings, while having the effect of reducing yellow light emission, are sometimes also very reflective. The result is that, instead of most of the light coming from the filament directly through the glass capsule and being used by the headlamp's optical design to have a focused beam down the road, the light bounces once or twice off the inner wall of the bulb. This causes strong images of the filament to be emitted from the capsule in directions and intensities never possible in the standardized OEM design. Because headlamps are designed to use standardized bulbs, the lighting performance of the headlamp could be markedly different, both impairing seeing down the road and causing others to have undue glare, when a modified, non-standardized bulb is substituted. Such poorly designed bulbs may also be a reason for the public's glare complaints.
In contrast, if the bulb designer uses a more benign filter element, the inner bulb reflectivity may be substantially reduced or virtually eliminated. For a bulb that is intended to be whiter, less yellow light may be emitted, giving the light a whiter, even bluish light, but still white light as defined in various industrial and legal standards. To assure that this bulb emits the equivalent and correct volume of light compared to an OEM version, the filament design must be subtly changed, but not so much so that wattage increases above the acceptable limits required of a standard bulb. These careful changes may continue to make the bulb interchangeable with an OEM design without noticeable consequence other than whiter light.
Besides replacing the OEM bulbs with bulbs with the characteristics described above, it is possible to purchase whole headlamps and replacement lenses for those that are replaceable, that are tinted. Under our standards, these must comply, with our lighting standard but again, the blue, or other color, tinting may have similar adverse disturbing and disabling glare effects .
Another disturbing trend in this look-a-like phenomenon is the substitution of OEM filament headlamp bulbs with aftermarket HID conversion bulbs. The desire is to achieve the look and achieve the more robust performance of HIDs. While not designed to be interchangeable, some aftermarket companies are substantially altering the HID bulb bases or providing adapters so that the HID bulbs can be inserted in headlamps designed for filament bulbs. The consequence of making these substitutions is to adversely affect safety. Filament headlamps are optically designed for the volume of light and filament placement and other critical dimensions and performance that OEM filament bulbs have. The HID conversions result in two to three times the volume of light and potentially imprecise arc placement. Such conversions often result in beam patterns that behave nothing like the original filament beam pattern, cannot be reliably aimed, and have many times the permitted glare intensity. In informal conversations with persons who have tested such conversions, the light intensity on one at a point aimed toward oncoming drivers was 22 times the allowable intensity limit. Another lamp was more than 7 times too intense. With poor HID bulb and arc placement, the glare intensity could be significantly worse. Thus, the use of these conversions could be yet another source of the glare problems about which many drivers have complained.
2.4 - Glare from Fog Lamps, Driving Lamps, and Auxiliary Low Beam Headlamps
Fog lamps, driving lamps, and auxiliary low beam headlamps are lamps used in addition to the normally required headlamps. These lamps have been identified in state laws for decades as being allowed to be used under certain conditions of visibility. Generally, as defined in SAE standards, fog lamps have a wide even beam, less intense than a low beam, and intended to be mounted low to shine out under blankets of fog hovering near the ground, and in other conditions of reduced visibility such as rain, snow and dust. Properly aimed, fog lamps can be used to reduce the back scatter glare that often results from water droplets, snowflakes and dust particles illuminated by headlamps. The fog lamp with its downward aimed beam can reduce that veiling glare and permit seeing, albeit at much shorter distance, the roadway and important targets. Speeds, of course, have to be reduced under those conditions.
Driving lamps are lamps not intended for general driving, but are intended to supplement the upper beam headlamps. In essence, they are auxiliary upper beam headlamps. As such, they should never be used under conditions that do not permit the use of upper beam headlamps. Their beam intensity and aim are described in SAE standards and often referenced in state motor vehicle law.
The Auxiliary Low Beam Headlamp, is just that, a lamp similar in beam pattern and performance to a lower beam headlamp. It is intended to supplement the lower beam headlamp, more typically for turnpike driving, where the roadway has widely separated opposing lanes.
More and more passenger cars and LTVs are being equipped with auxiliary lamps these days. As an OEM option, the lamps, usually fog lamps, offer different styling cues than the normal model vehicle to help differentiate it in the market. Also, the public may be interested in "better" lighting, because the number of both OEM and aftermarket installations is increasing markedly. Because of fog lamps' limited performance, they by design will not markedly improve seeing under normal conditions.
These auxiliary lamps are now becoming a source of complaint for glare. Often described as another set of headlamps, sometimes mounted lower, the public reports that these lamps seem to be used all the time at night. In fact, research has now documented that the public is right. Sivak et. al. reported that fog lamps were in fact used much more often than was appropriate for the conditions. In fact, most of the auxiliary lamps in the census were on regardless of the weather or visibility conditions, and most vehicles that had them installed had them in use (see Sivak, M.; Flannagan, M. J.; Traube, E. C.; Hashimoto, H.; Kojima, S. 1997, "Fog lamps: Frequency of Installation and Nature of Use," No. UMTRI-96-31, available as Docket NHTSA-1998-8885-1).
This documented misuse of fog lamps in particular helps substantiate the complaints that NHTSA has been receiving. NHTSA has had complaints about fog lamp use for a while, but never so many as recently. As part of another rulemaking (63 FR 68233, December 12, 1998), NHTSA asked whether it should regulate fog lamps in general, because it was petitioned to regulate the geometric visibility of fog lamps as installed on motor vehicles. The response by commenters to this question was unanimous: yes, please regulate them. NHTSA's authority to regulate their safety will have the consequence of having a common national standard for them. Some of the commenters suggested waiting until the SAE and other international organizations achieved a harmonized, but updated version of a fog lamp standard. As a result of that request, NHTSA has been waiting several years for this to occur. However, there appears to be significant disagreement within both the SAE's Lighting Committee and the Groupe de Travail Brusselles, 1958 , (GTB) as to what constitutes the current state of industry performance for fog lamps. For the foreseeable future, NHTSA has no expectation that a harmonized fog lamp performance consensus standard will be forthcoming from SAE or GTB. Because of the significant increase in complaints, NHTSA plans to propose action independently of outdated industry standards for fog, auxiliary and driving lamps to regulate these at the federal level.
"Educated and knowledgeable" statements by the NHTSA about HIDs and other types of illumination.
2.2 - Glare from High Intensity Discharge Headlamps
In the case of HIDs, we have received numerous complaints stating that these newer lamps produce excessive glare. Even though they are required to comply with all federal lighting requirements and we have no reason to believe that they do not comply, HIDs are still being singled out as being troublesome glare producers for other drivers. The reason expressed by drivers is that the HID headlamps are brighter. This may be due to the spectral content of the produced light, the generally wider and more robust beam pattern, and/or their conspicuous color relative to other headlamps, or misaim.
In an effort to create a headlamp which provides better illumination, longer life, and a unique styling appearance, vehicle lighting manufacturers developed HIDs. They have been typically offered on higher end vehicles and can cost as much a $400 to $800 for the option. HIDs are unlike conventional halogen headlamps in that they operate more like street lamps. Instead of heating a tungsten filament, an electrical arc is created between two electrodes. This excites a gas inside the headlamp (usually xenon) which in turn vaporizes metallic salts. These vaporized metallic salts sustain the arc and emit the light used for the headlamp's beam. These lamps provide more light than that produced by halogen lamps and only use two-thirds the power. As a result, they are more efficient, and because there is no filament to burn out, these bulbs are claimed to last for as much as 100,000 miles of driving time.
Although the agency has seen advertising and received many complaints claiming that the light produced by HIDs is twice or three times as bright as that which is produced by halogen lamps, laboratory measurement, made by various parties, do not support these claims. HID light sources (bulbs) typically have about two to three times the available light flux (volume) of halogen light sources, but because of such an abundance of light, the HID optical design does not necessarily need to be as efficient at collecting and distributing light as a halogen system. The HID beam pattern is certainly more robust, providing more even and wider illumination and the potential for better visibility and comfort. This performance results in more light on the road surface and more of the roadway being illuminated. However, this additional light is not supposed to be projected upward from the lamp toward other drivers' eyes. During inclement weather, when the road surface is wet, the additional volume of light can result in higher levels of light reflected off the road surface into other drivers' eyes. However, those who have complained about HID glare have not specifically reported inclement weather as the only time when there is a problem with HID glare.
Another factor that may be involved is the phenomenon that may have occurred with the introduction of halogen lamps in the early 1980's. Drivers are attracted to headlamps that are different colors than would normally be seen. As such, the drivers may look directly at oncoming headlamps during driving to see the unfamiliar item. This is something that they do not normally do. Initial halogen headlamp introduction elicited some glare complaints, even though the first halogens used were actually very similar in performance to the standard non-halogens headlamps. The only marked difference was the color of the halogen headlamps. If this is the case now, one would expect glare complaints about HIDs to stop when drivers become familiar with the HID color. NHTSA is aware of no studies or evidence to suggest that this theory is correct.
Another factor that may lead to the perception that HIDs are significantly brighter than halogen lamps is that human eyes may be more sensitive to bluish-white light of HIDs than to yellowish-white light of halogens. When observing some HIDs, it may seem that they are not emitting white light, as required by Standard No. 108. However, when observing the beam pattern projected on a white screen, HID headlamps that comply with our lighting standard will appear to be white with color separations occurring only at the extreme edges of the pattern. Non-halogen, halogen, and HID light sources appear to be different colors to observers. Non-halogen lamps appear to be yellow when compared to halogen lamps, and halogen lamps appear to be yellow when compared to HIDs.
In a recent study by the University of Michigan Transportation Research Institute (Flannagan, M. J.; 1999, ASubjective and Objective Aspects of Headlamp Glare: Effects of Size and Spectral Power Distribution," Report No. UMTRI-99-36, available in Docket Number: NHTSA-2001-8885-3) the differences reported between halogen versus HID lamps caused a small but statistically significant difference in discomfort glare noted by observers. However, it had no effect on disability glare. It is not known yet whether it is the difference in spectral power density of these headlamps, but this difference in the human eye's glare response to these different lamp designs is shown in that study.
HIDs are not just more white (having less yellow content and more blue content in the emitted spectrum), but the light is generated in a different manner. HIDs achieve light by having vaporized metallic salts participate in the electrical current flow through an arc in the bulb capsule. This is contrasted to a heated metal filament which gives a relatively even level of light at all colors in the spectrum, and thus achieves smoother white light. The HIDs blend of metallic salts is designed such that the different salts, emitting different colors of light with different energy levels, will complement each other when fully heated and electricity is passed through them, because each salt contributes various frequencies of light and at different levels of energy. The result is white light, but with a few relatively high energy spikes of light at very narrow bandwidths. These spikes are obvious in a mapping of the spectral power density of the light emitted. (See Docket Number: NHTSA-2001-8885-4, USA Today, June 7, 2001, "Bright Lights, Big Controversy" by James R. Healey, page 1, the side bar Aharsh blue light contributes to glare"). This comparison shows that the light spectrum of HIDs is not as smooth as the light from a heated filament in a halogen lamp. It is possible that our eyes are not necessarily reacting to the whiter light, but to the high energy spikes that rise above a background energy achieving the white light. If this is a cause for the UMTRI findings, it may be that a redesign of the HID system is necessary. However, this is just a theory, with no supporting data. NHTSA is initiating research to study all potential factors that may be causing HIDs to be an annoying lighting source.
2.3 - Glare from HID Look-alike Bulbs and Other Colored Headlamp Bulbs
The advent of HIDs on more expensive vehicles has spawned attempts at achieving halogen-based look-a-likes. These are achieved by using coated, tinted, filtered or otherwise altered glass capsules for the halogen headlamp bulbs that can be used in place of the OEM bulbs. Alternatively, aftermarket headlamp housings with similar coating, tinting and filtering are being sold as replacements for OEM headlamps. The goal of many of these bulbs is to emit light that is different than an OEM halogen headlamp bulb, while attempting to maintain a headlamp's legally complying performance. The whiter light is offered as being closer in color to natural daylight, thus the claim is that drivers see better with the same amount of emitted light. This is not unique in motor vehicle lighting history; in fact, it is the same claim and intent as accompanied the 1929 Tung-Sol Blue-Wite TM headlamp bulb. The yellow variants of colored bulbs are intended to be more useful in wet weather where the color, still measured to be white, is more yellow than OEM halogen bulbs. The intent is to offer a color of light less likely to be reflected back from precipitation and fog. At the other extreme of colored aftermarket bulbs, are those that are very blue or multicolored. The multicolored bulbs are the result of many different colors being emitted by the bulb in various directions, instead of white light being emitted in all directions as occurs in normal halogen bulbs.
Generically categorized as "blue" bulbs, all of these aftermarket bulbs have become popular among auto enthusiasts and some other drivers, either because the bulbs produce the look of a more expensive vehicle at a fraction of the cost, or claims of improved visibility. Many of the bulbs are from well known bulb manufacturers, others are from less familiar companies and importers. Depending on the make and model of bulb desired, some are sold by auto parts stores and mass merchandisers, others are sold by specialty auto accessory stores and through the Internet. While there are no reasons to believe that all such bulbs cause headlamps to perform badly, many such bulbs do just that, as explained below.
The designing original equipment headlamp bulbs is a precise science, fraught with many design compromises in order to achieve the desired balance of energy usage, service life, emitted light and robust optical images of the filament. In general, headlamp bulb designs take years of thoughtful work in consultation with the designers of headlamp optics. The OEM bulb design is standardized and codified by industry consensus in SAE and International Electrotechnical Committee (IEC) standards so that all bulb manufacturers can build and sell bulbs with the expectation that they will perform in a safe and satisfactory manner in all headlamps in service. This standardization is incorporated into Federal Motor Vehicle Safety Standard No. 108, Lamps, reflective devices and associated equipment (FMVSS 108) by referencing information about each bulb. This information is in Docket Number: NHTSA-98-3397.
When changing the basic design of a headlamp bulb the way that placing a coating, filter or tinting can, the results can range from just color changes to reducing the emitted volume of light from a headlamp by almost half. For example, certain kinds of filters and coatings, while having the effect of reducing yellow light emission, are sometimes also very reflective. The result is that, instead of most of the light coming from the filament directly through the glass capsule and being used by the headlamp's optical design to have a focused beam down the road, the light bounces once or twice off the inner wall of the bulb. This causes strong images of the filament to be emitted from the capsule in directions and intensities never possible in the standardized OEM design. Because headlamps are designed to use standardized bulbs, the lighting performance of the headlamp could be markedly different, both impairing seeing down the road and causing others to have undue glare, when a modified, non-standardized bulb is substituted. Such poorly designed bulbs may also be a reason for the public's glare complaints.
In contrast, if the bulb designer uses a more benign filter element, the inner bulb reflectivity may be substantially reduced or virtually eliminated. For a bulb that is intended to be whiter, less yellow light may be emitted, giving the light a whiter, even bluish light, but still white light as defined in various industrial and legal standards. To assure that this bulb emits the equivalent and correct volume of light compared to an OEM version, the filament design must be subtly changed, but not so much so that wattage increases above the acceptable limits required of a standard bulb. These careful changes may continue to make the bulb interchangeable with an OEM design without noticeable consequence other than whiter light.
Besides replacing the OEM bulbs with bulbs with the characteristics described above, it is possible to purchase whole headlamps and replacement lenses for those that are replaceable, that are tinted. Under our standards, these must comply, with our lighting standard but again, the blue, or other color, tinting may have similar adverse disturbing and disabling glare effects .
Another disturbing trend in this look-a-like phenomenon is the substitution of OEM filament headlamp bulbs with aftermarket HID conversion bulbs. The desire is to achieve the look and achieve the more robust performance of HIDs. While not designed to be interchangeable, some aftermarket companies are substantially altering the HID bulb bases or providing adapters so that the HID bulbs can be inserted in headlamps designed for filament bulbs. The consequence of making these substitutions is to adversely affect safety. Filament headlamps are optically designed for the volume of light and filament placement and other critical dimensions and performance that OEM filament bulbs have. The HID conversions result in two to three times the volume of light and potentially imprecise arc placement. Such conversions often result in beam patterns that behave nothing like the original filament beam pattern, cannot be reliably aimed, and have many times the permitted glare intensity. In informal conversations with persons who have tested such conversions, the light intensity on one at a point aimed toward oncoming drivers was 22 times the allowable intensity limit. Another lamp was more than 7 times too intense. With poor HID bulb and arc placement, the glare intensity could be significantly worse. Thus, the use of these conversions could be yet another source of the glare problems about which many drivers have complained.
2.4 - Glare from Fog Lamps, Driving Lamps, and Auxiliary Low Beam Headlamps
Fog lamps, driving lamps, and auxiliary low beam headlamps are lamps used in addition to the normally required headlamps. These lamps have been identified in state laws for decades as being allowed to be used under certain conditions of visibility. Generally, as defined in SAE standards, fog lamps have a wide even beam, less intense than a low beam, and intended to be mounted low to shine out under blankets of fog hovering near the ground, and in other conditions of reduced visibility such as rain, snow and dust. Properly aimed, fog lamps can be used to reduce the back scatter glare that often results from water droplets, snowflakes and dust particles illuminated by headlamps. The fog lamp with its downward aimed beam can reduce that veiling glare and permit seeing, albeit at much shorter distance, the roadway and important targets. Speeds, of course, have to be reduced under those conditions.
Driving lamps are lamps not intended for general driving, but are intended to supplement the upper beam headlamps. In essence, they are auxiliary upper beam headlamps. As such, they should never be used under conditions that do not permit the use of upper beam headlamps. Their beam intensity and aim are described in SAE standards and often referenced in state motor vehicle law.
The Auxiliary Low Beam Headlamp, is just that, a lamp similar in beam pattern and performance to a lower beam headlamp. It is intended to supplement the lower beam headlamp, more typically for turnpike driving, where the roadway has widely separated opposing lanes.
More and more passenger cars and LTVs are being equipped with auxiliary lamps these days. As an OEM option, the lamps, usually fog lamps, offer different styling cues than the normal model vehicle to help differentiate it in the market. Also, the public may be interested in "better" lighting, because the number of both OEM and aftermarket installations is increasing markedly. Because of fog lamps' limited performance, they by design will not markedly improve seeing under normal conditions.
These auxiliary lamps are now becoming a source of complaint for glare. Often described as another set of headlamps, sometimes mounted lower, the public reports that these lamps seem to be used all the time at night. In fact, research has now documented that the public is right. Sivak et. al. reported that fog lamps were in fact used much more often than was appropriate for the conditions. In fact, most of the auxiliary lamps in the census were on regardless of the weather or visibility conditions, and most vehicles that had them installed had them in use (see Sivak, M.; Flannagan, M. J.; Traube, E. C.; Hashimoto, H.; Kojima, S. 1997, "Fog lamps: Frequency of Installation and Nature of Use," No. UMTRI-96-31, available as Docket NHTSA-1998-8885-1).
This documented misuse of fog lamps in particular helps substantiate the complaints that NHTSA has been receiving. NHTSA has had complaints about fog lamp use for a while, but never so many as recently. As part of another rulemaking (63 FR 68233, December 12, 1998), NHTSA asked whether it should regulate fog lamps in general, because it was petitioned to regulate the geometric visibility of fog lamps as installed on motor vehicles. The response by commenters to this question was unanimous: yes, please regulate them. NHTSA's authority to regulate their safety will have the consequence of having a common national standard for them. Some of the commenters suggested waiting until the SAE and other international organizations achieved a harmonized, but updated version of a fog lamp standard. As a result of that request, NHTSA has been waiting several years for this to occur. However, there appears to be significant disagreement within both the SAE's Lighting Committee and the Groupe de Travail Brusselles, 1958 , (GTB) as to what constitutes the current state of industry performance for fog lamps. For the foreseeable future, NHTSA has no expectation that a harmonized fog lamp performance consensus standard will be forthcoming from SAE or GTB. Because of the significant increase in complaints, NHTSA plans to propose action independently of outdated industry standards for fog, auxiliary and driving lamps to regulate these at the federal level.
SUMMARY
1. Factory fitted HIDS are not a problem (in fact are better than halogens: are more efficient, consume 2/3 of the power and last up to 100k miles). Factory HIDS are usually 2-3 times brighter than halogens but will not blind drivers because the light is targetted differently by the lens (focussed lower and wider). Drivers eyes are attracted to them as they are still unusual, and some may experience slight discomfort due to spikes in light spectrum emmitted, but there is no danger.
2. Aftermarket HIDS headlamp units (designed for and including HID bulbs) are usually OK too.
3. Aftermarket HID bulbs can definitely be a problem for glare, because the halogen headlamp lens they are fitted into is not designed to properly focus the brighter light in a wider/lower beam (can focus up to 22 times the permitted light at oncoming drivers).
4. Fog lights are used unnecessarily and can cause glare - there is a move to have an industry standard fog-light (will never happen) and to regulate their use better (federal proposal - may happen one day).
02-28-2003, 02:52 PM
#20
Prodigal Wankler
Re: Re: from the NHTSA archives
Originally posted by pelucidor
I read it ALL - gold star for me.
I read it ALL - gold star for me.
03-03-2003, 08:33 AM
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Originally posted by eccles
Fine, you go ahead and squint. Me, I want as much light out front as I can possibly get. Having driven cars with HID and projector-style halogen lights, I can assure there's no comparison - the HID's win hands down.
Fine, you go ahead and squint. Me, I want as much light out front as I can possibly get. Having driven cars with HID and projector-style halogen lights, I can assure there's no comparison - the HID's win hands down.
05-11-2004, 10:53 PM
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I just bought an RX-8. I opted out of buying the Sport package on the premise that I could upgrade later with aftermarket parts. I have been looking at systems from a company called Mecca Tune and Hella. Has anyone done an aftermaket install on the lights themselves, and what are your recomendations for this action? Also, I looked in the engine bay for spaces to mount the ballast and the ingitor, and little room is availible. What are your thoughts and opinions?
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