Smart & Connected Life Connected Car Tech 53 53 people found this article helpful Are Aftermarket Blue Xenon HID Headlights Legal? by Jeremy Laukkonen Writer Jeremy Laukkonen is tech writer and the creator of a popular blog and video game startup. He also ghostwrites articles for numerous major trade publications. our editorial process Facebook Twitter LinkedIn Jeremy Laukkonen Updated on January 29, 2020 Connected Car Tech Android Auto Apple Carplay Navigation Tweet Share Email High-intensity discharge (HID) headlights have a lot of advantages over halogen headlights. They're brighter, put less of a load on the alternator, and the hotter color temperature makes it easier to see things like road signs at night. You may have even seen these blue or white headlights on older cars and wondered if it's possible, or legal, to upgrade your car with aftermarket HID xenon lights. Some of the cars you see on the road that have white or blue headlights came with high-intensity discharge (HID) lights from the factory, and they are totally legal. Other cars you see with blue headlights have questionable aftermarket modifications that can make it tough for other drivers to see at night, and may even result in a ticket. Michael Bodmann / E+ / Getty Images This is a pretty complicated subject when you get right down to it, but the simple answer is that you should check into the specific laws where you live before you put anything other than a stock replacement headlight bulb in your car. Stock Halogen vs. High-Intensity Discharge Lights The reason that the issue of aftermarket headlights, often referred to as white or blue headlights, HID headlights, or xenon headlights, is so complicated is that there are two kinds of aftermarket replacement headlights that can appear blue, and they use totally different technologies. Some "blue" headlights are just regular halogen capsules with a blue film, while others are actually a totally different type of light technology. Most cars that are on the road today use either sealed-beam halogen headlights, or capsule-style halogen headlights where each headlight consists of a permanent reflector assembly and a halogen capsule. The first type requires you to replace the entire lens and bulb assembly together, while the other allows you to simply pop a new halogen capsule into the permanently-installed reflector assembly. Factory HID lights are similar to the second type, but instead of a reflector designed for a halogen capsule, they utilize a projector assembly. What that means is that while you can buy HID capsules that will slide right into your factory headlight assembly, doing so can create issues with bright, unfocused beans that shine all over the place and can consequently cause problems for other drivers. Where the NHTSA Stands on Aftermarket HID Headlights Currently, most jurisdictions in the United States require headlights to conform to Federal Motor Vehicle Safety Standards (FMVSS) 108, which states that replacement headlight capsules must match the dimensions and electrical specifications of the factory equipment. This is an issue due to the fact that HID headlights don’t work the same way that halogen headlights do. For instance, HID headlights utilize a ballast, which halogen capsules don’t require. The NHTSA takes a very narrow view as to what it takes to conform to FMVSS 108. According to the Washington State Patrol, for example, an HID replacement for an H1 halogen bulb would have to precisely match an H1 bulb’s filament size and placement, electrical connector, and ballast, which is categorically impossible due to the fact that H1 bulbs don’t use ballasts in the first place. Additionally, the NHTSA found that HID conversion kits often exceeded the rated output of factory headlights, often by a great deal. In some cases, aftermarket HID headlights have been measured in excess of 800 percent of the maximum candlepower of the halogen headlights they were meant to replace. Don’t Believe the DOT You may have heard that it’s okay to install an HID conversion kit if it has a DOT logo on it, but the fact is that this mark only means that the company that manufactured the product has self-certified that it meets federal requirements. The NHTSA, which is part of the United States Department of Transportation, is responsible for setting requirements, but it doesn’t actually certify that any given product meets those requirements. So while there is such a thing as conforming to DOT standards, there's no such thing as a DOT-approved headlight. Since the NHTSA has gone on record as saying that it isn’t possible for an HID conversion kit to conform to FMVSS 108, any “DOT approved” label on aftermarket HID lights should be taken with a grain of salt. As always, it’s important to investigate exactly what the product is, and whether or not it is actually legal, rather than just taking someone’s word for it. Legitimate Aftermarket HID Retrofits Since some cars come with HID headlights from the factory, HID headlights clearly aren’t unsafe in and of themselves. In fact, if you replace your headlight reflector assemblies with appropriate projector assemblies, aim them properly, and the install work is professionally done, you’re likely to end up with a safe upgrade that won’t blind other drivers. However, you could still get pulled over, and you could still end up with a ticket, depending on how the laws are worded where you live, and the priorities of the local police department. In fact, it’s entirely possible that you could be pulled over simply for driving around with halogen bulbs that have a blue coating to approximate the look of HID lights. As to whether the ticket would actually stand up in court, that, again, depends on the specific laws where you live.