1995 Buick Regal with HID kit

Are HID Kits Legal or Safe?

Many people decide they want to install an HID kit in their car because they think it will give them improved visibility and because it looks cool. Few people stop to ask if it’s safe or if it’s legal. I’m here to tell you the truth about HID kits and whether or not they are safe or legal to use.

The truth is, HID conversion kits are not only illegal, but also unsafe both for yourself and for other drivers on the road. I’m referring to these xenon bulbs that come in a box with bulbs, ballasts, and a few wires, which I will refer to in this article simply as “HID kits.” Allow me to explain.


Reflectors vs Projectors

To start, the first fundamental issue of using HID bulbs in a car in which they were not equipped is that the headlight housing is not calibrated for it. If your car was equipped from the factory with halogen bulbs, your headlight housings will be calibrated to allow a specific amount of glare to be released above the horizontal plane. This helps you illuminate road signs, and give you a small amount of visibility above where your headlight beam would normally project without requiring the use of your high beams. The problem with this comes when you install HID kits and don’t stop to consider the amount of glare that you’re sending above that horizontal plane and into the eyes of oncoming drivers.

To give you some perspective, older peoples’ eyes take up to 8 times as long to adjust to intense light fluctuations (more on that later). While the increased light output will not bother you, the story is completely different when you’ve multiplied the amount of glare your headlights are producing against 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 headlights are producing.

I was able to find a few pictures that will demonstrate what I’m referring to. The following is a picture I took of my Chevy Cruze with factory halogen bulbs. I placed a bag with golf clubs in front of the left headlight in order to demonstrate how much glare is actually being produced by this car, which some have actually noted has a great “cut-off” line.

Chevy Cruze Halogen Headlight Beam

As you can see by the shadow cast on the garage door by the golf club bag and the clubs themselves, this car emits a significant amount of glare above the horizontal plane, or “cut-off line.” The following picture was taken of the light output of another Chevy Cruze with a 35W 8000K HID kit installed:

Chevy Cruze HID Headlight Beam

Here, you can see a significant amount of glare being directed above that cutoff line. To provide a comparison point, here’s what a factory HID beam looks like through a calibrated projector lens:

HID Projector Beam Cutoff

You’ll notice that there is a much greater and more distinct separation between the projection of the light beam and the emission of glare above that projection.


Filament Location

Have you ever taken the time to look at the source of the light between an HID bulb and a Halogen bulb? If you have, you’ll notice that the source of the output (whether it’s the capsule in an HID bulb or the filament in a Halogen bulb) is different between the two.

Halogen vs HID Xenon bulb Filament

The problem this creates is that it changes the shape and projection of the light beam that your headlight housing was designed for. Anyone who has played with a MagLite flashlight before will know precisely what I’m talking about. 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.

Now, I’m sure some of you will ask, “But, can’t I just aim my headlights down to prevent all of this glare?” My answer to you is: “then what’s the point?” The purpose of an HID bulb is to provide you with superior visibility. 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.

The general rebuttal to all of this is typically “but I don’t care about that. I just want it to look cool.” The notion here is that anyone installing these HID kits is doing so because they cannot afford to purchase new headlight housings calibrated and designed for HID bulbs. It can be easily deduced that if one cannot afford new headlight housings, that one cannot afford a fine in the event that they are caught doing something illegal.


HID Kits: Are they Legal?

The short answer is: NO. HID Kits are not legal.

The long answer is this: NHTSA (National Highway Traffic and Safety Administration) has ruled that HID conversion kits are not only undoubtedly unsafe, but also illegal. People who I have personally talked to have received fines upward of $250 for their use of an illegal modification. They are not DOT approved, and are specifically sold as “for off-road use only.”

While your local police officers may not pull you over for having illegal HID bulbs in your car, they may be more than happy to tack on a fine if they have reason to pull you over for something else or if you’re unlucky to catch an officer who is having a bad day or needs to meet a quota.



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

Click to access Government-Affairs-2009-09-eNews-May07-Lighting-HID-Conversion-Kits.pdf

NHTSA has concluded that it is impossible to produce HID conversion kits (converting a halogen system to HID) that would be compliant with the federal lighting standard, Federal Motor Vehicle Safety Standard (FMVSS) No. 108. The noncompliant kits frequently include an HID bulb, ballast, igniter, relay and wiring harness adapters. NHTSA believes this equipment presents a safety risk to the public since the kits can be expected to produce excessive glare to oncoming motorists. In one investigation, NHTSA found that an HID conversion headlamp exceeded the maximum allowable candlepower by over 800 percent.


To date, NHTSA has investigated 24 HID conversion kit suppliers; all investigations have resulted in recalls or termination of sales.

These illegal lights are a potential hazard to those who share the road,” said NHTSA Administrator Jeffrey Runge, MD. “And we will continue to pursue those offering them for sale and violating the law.”

Companies that sell, import or manufacture non-compliant equipment could face substantial civil penalties, NHTSA said.


HID Bulbs, Glare, and Other Drivers

Earlier, I mentioned that it takes an older person up to 8 times a long to adjust to fluctuations in light intensity. While the following may relate to both factory installed HID bulbs as well as conversion kits, the point remains that these conversion kits vastly amplify the effects that I’m about to describe. This section is here to explain why the installation of HID bulbs affects more people than just yourself.

According to AAA:

Drivers middle-aged and older are more sensitive to glare than younger drivers because their eyes take longer to adjust to changing light levels. For example, a 55-year old takes eight times longer to recover from glare than a 16-year-old.”

studies at the University of Michigan’s Transportation Research Institute indicate that the bluish tint of xenon HIDs produces substantially more dazzle. Subjects rated glare after being confronted by halogen or HID illumination at different intensities. Researchers collected subjective ratings as well as intensities measured at the subjects’ eyes. Halogens operating at [many] times the intensity of the HIDs gave the same perceived glare.

From NCBI (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1771460/)

Glare is proportional to headlamp brightness, however, so increasing headlamp brightness also increases potential glare for oncoming drivers, particularly on curving two lane roads. This problem is worse for older drivers because of their increased intraocular light scattering, glare sensitivity, and photostress recovery time.

…HID headlights are brighter than conventional tungsten-halogen headlights. Thus, they cause more disability glare under identical viewing circumstances.


“So, what are my options?”

I hate to leave people without any real alternatives when discussing HID kits, so I will present you with a few options that will allow you to safely install HID kits in your car.

Your best option is to purchase new headlight housings that have projector lenses already installed. Websites such as CARID.com sell these housings for very reasonable prices. These housings are designed for use with HID bulbs and will provide truly improved lighting with regard to both viewing distance and with regard to

If you own a vehicle that you cannot find any upgraded headlight housings for, consider installing a retrofit. TheRetrofitSource.com is a website that sells Projector retrofit kits. Using their “discard pile” projectors (often just older version stock), you can install projectors for as little as $135 including the bulbs. Their sales staff is very knowledgeable and would be more than happy to recommend specific components that you would need for your vehicle. These projector retrofits require the dis-assembly of your headlight housing and the installation of a projector lens in the hole through which your factory halogen bulb is installed. These make leave no permanent modification and can be reversed at any time.

If you are simply looking for improved lighting, consider an upgraded bulb such as a Sylvania XtraVision or a Philips X-Treme Power bulb. These bulbs offer improved output while remaining within safe limits, often at the expense of a shortened bulb life. I personally use Sylvania XtraVision bulbs and have driven 14,000 miles with my set without a failure.

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