Q: I’m curious to know if there are any standards for car headlights as to intensity, angle and color. When I drive night I see cars which have very bright lights (as opposed to just high beams) and some cars with a range of colors (white, yellow and even a tint of blueness). If you can shed any light (pun unintended), I’d be pleased.

A: We just passed the fall equinox and entered the half of the year when there’s more darkness in 24 hours than light, so this is a perfect time to talk about headlights. As more of our driving occurs during time when headlights are required, you may want to make sure that your headlights are doing what they’re supposed to do. They should of course illuminate the road for you. One thing we don’t often consider with headlights though, is what they can do to help (or harm) other drivers.

Before we get to colors, let’s start with basic functionality. When’s the last time you checked to make sure all your vehicle lights are working? Next time you have one minute and a passenger with you, start your trip by having your passenger get out and check while you use your headlights, brake lights and turn signals. The law requires working lights, but I don’t think that should be the main motivation; you want to see where you’re going and know that other people can see you.

Along with making sure your lights work, your headlights should be properly adjusted to simultaneously provide the best illumination for you and avoid blinding other drivers. If they’re aimed too low, you can’t see far enough ahead; too high and you’ll have other drivers flashing their lights at you thinking you have your high-beams on. Often a too-bright headlight is actually a misadjusted one.

You’re not alone in your observations about headlight colors. Several readers have mentioned seeing unexpected colors coming at them. One wrote, “I have seen purple, pink, green, blue and, most alarming, red halos around oncoming headlights. It is disturbing to have a vehicle approaching with colors that should be reserved for tail lights.”

First of all, you’ll see some color variation in legal headlights, ranging from a hint of amber to a hint of blue, depending on the color temperature of the bulb, but they’re still basically white. That’s not what this is about. Aftermarket vehicle lighting offers a lot of options for headlights, and many of them are not legal. However, you’ll have a hard time finding the specific law in the Revised Code of Washington. Our state, like most others, has adopted the Code of Federal Regulations on vehicle equipment (FMVSS 108), which in turn requires headlights to conform to SAE headlamp performance standards, where it is clearly stated (if you can wade through the 100 plus pages of rules) that, “The color of a headlamp shall be white.” Regarding the headlights with red halos that one reader saw, the law clearly prohibits red light visible from the front of the vehicle.

When you’re shopping for lights, here’s some advice: Only buy lights that meet the standard of the original lights in the car. Diverge from color and brightness requirements and the only time you’ll be allowed to turn them on is when the vehicle is not in motion and parked on private property.  I get that people like to express themselves with their vehicles. But it can’t be at the expense of safety. Maybe instead of illegal lighting, add a racing stripe or some custom flames.

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