The good thing about HID units is that they are an excellent and a safe amenity if fitted completely and not in parts. The reason, why majority of people face the ‘blind-effect’ from both, the on-coming and overtaking cars, is that these cars are generally fitted with HID bulbs and not a complete HID unit. So I have taken the liberty of compiling my research on HIDs in the form of FAQs, which might help in raising awareness regarding the use of HIDs.
1: Is there a limit on the brightness of HIDs?
It’s hard to say anything solid on this front, as my research yielded, there’s nothing solid for me to comment on. However, the brightest HIDs are 4100k ~ 4300k (white lights) found in BMWs and Audis. Then Infiniti’s come with 5000k ~ 6000K factory-fitted HID’s, which have more of a blue tint, but actually are not as bright. It is hard to find any other car manufacturer who fits higher output HIDs higher than 6000k, because that would defeat the safety purpose of having HIDs. Although some people install aftermarket HIDs: 8000k or higher for two reasons:
- Pure cosmetic and showing off purposes. Primarily because they have a more blue / purple tint to their light.
- Misconception of having higher ‘K’ values is better.
Cars with HIDs have headlamps designed for their higher intensity, namely factory calibrated projector lenses. So, what’s the issue with the after-market HIDs? Cars with aftermarket HID kits, produce a lot more glare, because the headlamps are not designed for HIDs. It’s the glare that causes blind effect on oncoming traffic and pedestrians. Here you might be wondering, what about SUV’s with factory fitted HIDs? They have the similar ‘blind effect’ from behind. Well, the answer is their elevated height and design constraint, the light beam is being projected from a higher angle and naturally cars have a lower ride height, so light beams projected from SUV’s will end up blinding you. But I noticed that if you pass them from the opposite direction, they don’t blind you that much, not more than halogen-bulb-fitted SUV’s.
Don’t believe me, find any Imported SUV, which comes with factory installed HIDs, and look at it’s headlamps from the side and you will notice glow, which won’t have a ‘blind effect’. But walk right in front of it (when the car is not moving) kneel down and look at the headlight, you’ll be blinded for sure! This is not the case for cars with regular reflective headlights or cars with a partial aftermarket HID kit. You’ll be blinded from the side, standing up as well. This is due to the lack of shielding, causing the light to ‘go everywhere.’
Also Read: Is it Legal to Install HID Kits in Pakistan?
2: Are color temperature and light intensity a factor in HIDs?
Academically, color temperature and light intensity are not the same thing. You can have 2900K bulbs that are brighter than 6000K bulbs. The measure of brightness, or light intensity is in the units of lumens. According to US DOT, an HID bulb roughly outputs 3000 lumens, depending on the lamp assembly, low-beam driving headlamps are required by US DOT to put out anywhere between high 800-1300K for incandescent, 2800-3200K for HID.
3: Why HIDs are manufactured to output more light?
There are two reasons for their obnoxiously: bright, color, and glare control, or lack thereof.
The lack of any proper regulatory authority in majority of countries has led to lackluster manufacturing and implementing polices of HIDs. Take US as an example,
- USDOT standards – includes a fair amount of stray light to be projected upwards from the cut-off point. However, tighter controls in European countries require auto-levelling on HID units, headlamp washers for the same (again, to prevent scattering), and all cars, regardless of their headlamp mounting height, are required to meet the same beam drop-off, vs Rest of the world, where majority of the cars have the same X degree per Y feet drop from the center of the headlamp as a suburban; meaning lights from the latter often end up lighting up the aircon vents of any lower cars ahead of it.
- Second reason is the color. The fact is, blue is rather offensive. When HIDs first came out, in mid 90s -It was an optional feature for top of the line cars – the marketing departments made a choice to have HID vs incandescent visually distinguishable in order to make them identifiable. Enter the optional extras of acquiring these bright lights. And thus the concept of ‘Brighter & Expensive is better’, was utilized once again.
But the above mentioned observations are for factory installed HIDs, what about the after-market stuff? I am afraid, due to less than efficient regulatory authorities’, stringent controls, and no check & balance on light emissions, these factors have bred the mentality of ‘Brighter & Expensive is better’, which is a recipe for disaster. Arguably, there is a limit to what a person is willing to spend on their headlight units, and vast majority of these people are not willing to bear the full expenses of a complete HID unit. This makes you wonder, what exactly is the point of installing only HID bulbs without calibrated lenses? After all, the purpose of HIDs is to provide safe and superior light quality. That is why there is a choice when you go out to HID shopping in the market:
- The mentality of ‘look I have blue lights and I paid special for these’
- The mentality of ‘Cost + Engineering + Vision = Full HID unit and superior night visibility’
Interestingly, automakers have started to add an incandescent source with projector headlamps, forgoing HIDs altogether in some of their product line-ups. This light- source will appear to be blue or green or purple, off-axis (viewed anything but head on), which is due to diffraction. Even good HID units (2001+ BMW 3 series, for example) appear white on axis and blue off axis because of diffraction. It appears that some makers have decided that the blue fringe at the lights’ cut-off point (due to diffraction) is a notable ‘feature’ to let the driver and others’ know about the nature of a special lighting source, and thus have increased the volume of blue fringe.
The bottom line in the above mentioned story is, a ‘well’ sorted out HID assembly is fantastic, but very few cars fit this criteria.
4: Difference of filament or source?
Not many people know this or they just choose to ignore it but the placement of filament is quite different in both HID bulb and a halogen bulb. More specifically, the source of the output (whether it’s the capsule in HID bulb or the filament in a Halogen bulb) is different between the two.
You might be wondering about what’s the reason behind stating an obvious fact. Well to put it simply, this difference changes the shape and projection of the light beam that your headlight housing was designed for. Take a tactical flashlight as an example, as you move the source of the light output farther away or closer to the base of the reflector, the beam changes. Considering that a headlight housing designed for Halogens was calibrated for a specific bulb, it is certain that changing the physical properties of the bulb will negatively change the projection of the beam.
At this point, some of you might be thinking, “Maybe I can aim my headlights downwards to prevent all this glare?” Well you can but then what’s the point with installing an HID kit? As far as I know, the purpose of an HID bulb is to provide superior visibility in the dark. If you’re forced to aim your headlights at the ground, you fool your eyes into thinking that your light output is better than it is. Your eyes will automatically adjust their exposure to bright light. If you’ve ever walked into a dimly lit room after being outside on a bright sunny day, you’ll notice that your eyes will take a while to adjust. In this regard, your eyes will adjust to the brighter light, making it more difficult for you to see more dimly lit light off in the distance or on the side of the road. This actually reduces your visibility and can put you in an unsafe situation, should an unexpected event occur, such as an animal crossing the road.
5: Is it dangerous to use HID bulbs?
To put things into perspective, according to a study published in the American Academy of Pediatrics, older people’ eyes take up to 8 times as long as to adjust to intense light fluctuations, as compared to the younger people. There is a good possibility that this bright light may not affect you sitting inside the car. The story, however is completely different when you’ve multiplied the amount of glare your headlights are producing against the oncoming traffic. A typical 55W halogen bulb will produce around 1000 lumens. By comparison, a 6000K 35W HID bulb will produce around 2800 lumens. You’re nearly tripling the amount of glare that your car’s headlights are producing.
Also Read: Misuse of HIDs Claims Yet Another Life
And then there is the fact that normal headlamps are not built to handle the amount of heat generated by these bright HID bulbs and thus their use has been reported to cause a meltdown of headlamps and a short circuit in a cars’ electronics.
You can also participate or read the discussion on using HID’s in Halogen Reflectors Housing on PakWheels Forums!