Question: “I’m wondering if there is a law regarding how bright headlights in automobiles can be. They seem to be very bright in a lot of vehicles these days. These lights make it very hard to see when they are coming at you.” — Dan, Roy
Answer: Yes, there is a law governing the brightness of vehicle headlights. The state administrative code has adopted Federal Motor Vehicle Safety Standards and Society of Automotive Engineers standards for aftermarket headlights and other lighting devices.
The standards outline the characteristics of headlights, including their color – which must be white – and their intensity.
Some newer high-intensity discharge (HID) headlights burn hotter than a regular bulb and emit a bluish tint, but they still are considered white as tested under the federal standard.
Lighting manufacturers must certify that their products meet the standard. Compliance usually is indicated on the packaging and with a Department of Transportation acronym on the base of the bulb. If the package states, “Not intended for road use” or “Off-road only,” it does not comply with the federal standard.
The Washington State Patrol warns against using kits that convert a halogen bulb to a HID headlight. The National Highway Traffic Safety Administration has determined the kits do not comply with the federal standards, so a converted headlight wouldn’t be legal in Washington.