Mr_twister/Getty Images Most of us have, at some point or another, been blinded by an oncoming car's obnoxiously bright headlights. Modern LED-equipped cars are bad enough, but older cars that have been retrofitted with LEDs are invariably worse — they're always too bright, never aimed low enough, and nearly universally headache-inducing. So why does the National Highway Traffic Safety Administration allow such distractions on to American roads? Well, it doesn't. It just can't stop them either. According to NHTSA's collection of Federal Motor Vehicle Safety Standards, LED retrofit headlights are illegal. Normally that would sound like the end of a problem, rather than the beginning, but there's another issue at play here: Actually enforcing the law. See, NHTSA regulates automakers rather than auto modifiers, and the administration has no means of enforcing its anti-LED-retrofit law on the average car owner with a wrench and a couple hundred bucks in AutoZone gift cards. Enforcement of laws around modified vehicles is a state issue, not a federal one, and states often have bigger fish to fry than some headlights. States' rights, or something Alena Savina/Getty Images There are, of course, plenty of reasons why drivers would want LED headlights at the front of their cars (beyond the obvious spite). LEDs last longer than other kinds of bulbs, and they're brighter — who doesn't want to see more at night? The problem is, most older halogen bulb housings aren't designed with LEDs in mind. They're shaped to reflect the light that a halogen bulb emits, and LEDs spread light differently. Next time you're blinded on the highway, know that the person drawing your ire is, in fact, breaking federal law. There's just no one on the federal level who can stop them, and the state authorities likely have better ways to spend their time. Still, have a bit of empathy — the person blinding you with their lights likely doesn't mean to, and may well be trying to correct for overly-dim lights on their own car. They're just a little dim about the workings of reflectors.