Why are car headlights so blindingly bright now?
Glaringly bright, blue-hued headlights filled my hatchback earlier this year as I drove 80 miles an hour on the highway between San Antonio and Austin. The headlights shone so brightly that their reflection in my rearview mirror burned my eyeballs, causing me to look away from the road and rapidly slow down. The large luxury SUV behind me began riding my tail causing an even more intense glare to engulf my car before aggressively whipping around to pass me.For a moment, all was fine. My eyes adjusted. And I began to pick up speed again only to be visually assaulted by a lifted truck with even brighter headlights and flood lights atop its roof, then an electric vehicle with the whitest lights Id ever seen, and an onslaught of others. Fearing my car being slammed from behind every time I was forced to slow down and look away from the road, I got off the highway and took an alternative route. The headlights felt like theyd become especially hard on my eyes in recent years. Maybe I was just getting old, I thought, or my eyes had been weakened by working on a computer for a living. Then a listener of Voxs Explain It to Me podcast named Reed called and asked, Am I going crazy? Or does every new car on the road have the worlds brightest headlights? Im wondering why this is suddenly happening? And are there any limits? Can people just put whatever they want on the front of their car and blind everyone else? He wasnt alone. Our show has received multiple emails with similar inquiries from listeners and Vox readers. And theres even a subreddit dedicated to the topic, where people complain, make jokes, and work together to find solutions. So in hopes of helping Reed, myself, and the many other upset drivers, Explain It to Me took on Reeds question. There are two ways to answer that question, lighting scientist John Bullough, who leads the Light and Health Research Center at the Icahn School of Medicine at Mount Sinai, told Vox. The first has to do with the color of LED lights, the kind now overwhelmingly used in car headlights. Youve probably noticed that a lot of them look a lot more of a bluish white compared to the yellowish white of halogen headlights, Bullough said, which used to be more common in headlights.The concepts we use to measure light intensity lumen and candela were created by scientists long ago, and dont fully align with how different parts of our vision have different sensitivities to different-colored lights, Bullough said. That means that even though a light meter might say a pair of halogen headlights has the same light intensity as a pair of LED headlights, our eyes will see the bluish LED one as brighter because its more likely to be picked by our peripheral vision, making our brains prioritize it as important or alarming. The second factor, Bullough said, is that the intensity of headlights really has increased over the last 10 to 20 years.If we think about the reason we have headlights, theyre not to create glare theyre to help us see things along the road so that we can avoid collisions, he said. But the result has been that moves to make cars safer for their occupants, like the ever-increasing size of American vehicles and the increasing intensity of headlights, have created a new set of safety problems for anyone outside the car. Whos responsible for the brighter lights? Headlight intensities have actually been increasing in part because of things like the Insurance Institute for Highway Safetys safety ratings, which the insurance company-backed nonprofit doles out to help customers choose which car to buy, Bullough said. Carmakers also use the ratings as a selling point. When IIHS first started evaluating headlights nearly a decade ago, they were giving headlights pretty poor grades in terms of their ability to help us see things at night. Of 95 car models tested by IIHS in 2016, just two earned a good rating.A desire to improve safety ratings, combined with the growing dominance of LEDs in the broader lighting market, has driven carmakers to rapidly brighten their lights.LEDs are a new technology that took over pretty much everything in the lighting world in the last 15 years. Its arguably the biggest change in lighting technology since they first fired up an incandescent light bulb, said Nate Rogers, a freelance writer who wrote an extensive story in 2024 about headlight brightness. LEDs are more energy efficient. They last longer. It was a total sea change in the lighting world when LEDs came out, and over time theyve started to replace pretty much everything, and that includes car headlights.But Rogers also believes the federal highway safety czars, the National Highway Traffic Safety Administration (NHTSA), share some of the responsibility for why bright LED lights have become the norm on roads. They are the ultimate authority, he said. Any car that is driving on the road has to meet NHTSA standards.Several people I spoke to [from NHTSA] told me that the most complaints from drivers that the NHTSA gets are about car headlights [and] headlight brightness, Rogers said. But NHTSA has not created rules to limit the intensity of bright lights. Nor do federal safety ratings for car models consider the safety of anyone outside the car, as Vox contributor David Zipper explained last year only the safety of a given cars occupants is included. Are brighter lights actually dangerous? During his reporting, Rogers said, he never really found anyone disputing safety concerns tied to headlight glare. While he was often pointed to an IIHS study finding a 19 percent reduction in crashes for cars that have good safety ratings for their headlights, he added, its really hard to track whether or not someone else got into a crash after being blinded by another drivers headlights. Without that strict measurement of how dangerous car headlight brightness is, it seems that NHTSA is a little stuck and a little unsure about how to fix it, he said. Driver safety is just one aspect of the problem. The other has to do with people sharing the roads pedestrians and cyclists. The number of people killed by cars while walking has risen precipitously in the US in the last decade: According to a new report from the Governors Highway Safety Association (GHSA), pedestrian deaths are up 48 percent from 2014. Another GHSA report found that in 2022, approximately three-quarters (77%) of pedestrians killed in fatal crashes were struck at night.Mark Baker, founder and president of the advocacy group the Soft Lights Foundation, which aims to protect people from the harmful effects of LED lighting, thinks headlight intensity, in addition to the increasing prevalence of large cars on American roads, might be linked to the uptick pedestrian deaths at night. He theorizes that drivers blinded by bright headlights at night struggle to see pedestrians, and pedestrians may struggle to see as well. Theres just way too much light now, he said. Nobody can see you.Baker has lobbied Congress to get a hearing on the adverse impacts of LED headlights, and hes tried working with states to pass laws limiting headlight intensity. He has yet to score a victory, but has gotten more than 70,000 people to sign a petition called Ban Blinding Headlights and Save Lives!I have filed two petitions to the federal government: one to set a limit on maximum intensity, Baker said. Right now there is no overall limit on maximum intensity. And then theres no limit on the blue wavelength light. Thats the most debilitating light. It causes glare in your eyes. Its harder to see. Its also hazardous to our eyes. The fight is personal for Baker. I got knocked out of teaching, he said. LED headlights on the road and in his classroom tormented him an experience that eventually led to a diagnosis of mild autism. I couldnt go to work, he said. So I started devoting my time to try and figure out whats wrong with these LEDs. Ive since met other people that have similar reactions so severe that theyre considering thoughts of suicide because its just its torture for those of us that have autism.So if safety ratings incentivize carmakers to equip new cars with bright LED headlights, what do we do? There are a couple of solutions that could help protect drivers from glare, Bullough said. The first has to do where headlights are aimed. The light that comes from low-lights, the lights we drive around with most often, should be pointed down and toward the road, and not into the rear window of cars. But headlights can become misaligned after theyve been replaced, or after accidents.Headlight aim is something that some states, but not most, actually require as part of their safety inspections, Bullough said. So drivers could ask their mechanic once a year to have their headlight aim checked and to adjust it if needed.Headlight aim is often especially poor with older cars that have aftermarket LEDs on their cars, automotive and tech journalist Tim Stevens said. He thinks better enforcement of traffic safety laws could help.A lot of states like Michigan, for example, dont have any kind of annual inspection at all, he said. So it becomes an issue for the police to basically pull someone over if they think that someones headlights are too bright.NHTSA could also create headlight intensity limits, which state and local authorities could then use as a baseline for enforcement, Bullough and Baker pointed out. Certainly what could be done is some upper limits on the overall intensity from low-beam headlights, Bullough said. Stevens said carmakers are introducing new technologies that could help with the problem, like high beam assist or adaptive beam technology, which are supposed to dim headlights instinctively and automatically when the cars are coming up on traffic, pedestrians, and dark corners.Its been available in Europe and in the rest of the world for quite a few years, Steven said. Its only been made legal in the US since 2022, but because it takes a long time for auto manufacturers to bring new technology to market, its still taking some time for them to be able to bring these new headlights to the American market. For now, he added, the tech is only going to be on the newest and highest-end cars. So its going to be a long time before we see this on the majority of cars on the road.There are other tools and techniques that the average person can use to deal with headlight glare, like looking down and to the right while driving when there are bright lights passing you, or picking up a pair of blue light-blocking glasses. But Baker believes meaningful change will only come through civic action. The empowerment comes from listeners contacting the government, contacting me, joining up with the Soft Lights Foundation, and getting involved, he said. Lets fix this systemic problem.Youve read 1 article in the last monthHere at Vox, we're unwavering in our commitment to covering the issues that matter most to you threats to democracy, immigration, reproductive rights, the environment, and the rising polarization across this country.Our mission is to provide clear, accessible journalism that empowers you to stay informed and engaged in shaping our world. 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