Imagine if you could drive at night with your high beams on all the time, bathing the road ahead in bright light but without ever blinding other drivers.
In Europe and Asia, many cars offer adaptive driving beam headlights that can do this. ADB is a lighting technology that has been available for many years in other parts of the world including Europe, China and Canada, but not in the United States.
It can actually shape the light coming from headlights rather than scattering it all over the road. If there’s a car coming in the other direction, or one driving ahead in the same lane, the light stays precisely away from that vehicle. The rest of the road is still covered in bright light with just a pocket of dimmer light around the other vehicles. This way a deer, pedestrian or bicyclist by the side of the road can still be seen clearly while other drivers sharing the road can see, too.
In America, the closest we can get to that today are automatic high beams, a feature available on many new cars that automatically flicks off the high beams if another vehicle is detected ahead. But that still means driving much – or most – of the time using only low beam headlights that don’t reach very far. That can be dangerous.
US auto safety regulations enacted in 2022 were supposed to finally allow ADB headlight, something for which the auto industry and safety groups had long been asking for. But, according to automakers and safety advocates, the new rules make it difficult for automakers to add the feature. That means it will probably be years before ADB headlights are widely available in the US.
ADB-enabled headlights already are sold on some luxury cars in America. They just lack the software to perform the way they were designed to. Some American Mercedes drivers can enjoy a dazzling light display as they start up or shut off their cars at night. Moving streaks of light wash across the pavement or walls in front of the car like a glittering snowstorm. But, while driving, the lights work just like standard high beam, low beam headlights. Their adaptive capabilities aren’t enabled here because they still don’t meet US rules.
Some ADB headlights work like digital projectors, using a million or more LED pixels to project light patterns on the road. Even in the US, some Mercedes vehicles can project symbols like arrows or lines on the road to guide drivers. Less expensive systems in Europe and Asia use several thousand or even fewer light emitters, reflectors or shutter systems to create adaptive beams,
Allowed, but not yet
Until two years ago, US auto safety regulations, written for traditional headlights, simply didn’t allow for adaptive headlight technology at all. Light beams wrapping around other vehicles just wasn’t something the regulations could encompass so the technology wasn’t allowed here by default.
That changed in early 2022 when, after a decade of work on it, America’s National Highway Traffic Safety Administration finalized regulations for adaptive beam headlights. But because the US regulations are so different from those in other countries, with requirements so difficult to meet, automakers still can’t offer it here. It will be years before they can offer new, redesigned ADB headlights that meet the standards, auto industry sources say.
Many industry sources didn’t want to speak on the record about these regulatory issues, instead referring CNN to technical comments sent by their automotive lighting experts to NHTSA as part of the rule-making process.
Some automakers and safety groups, including Ford, Volkswagen and the Insurance Institute for Highway Safety, are asking NHTSA to reconsider the regulations to make it easier and less costly to offer these headlights in the US.
“We wish the regulation and testing would be reconsidered to accept what has already been proven around the world, including Canada, and was informed and supported by SAE,” Audi, VW’s luxury brand, wrote in a statement provided to CNN. “Many of our cars equipped with matrix design or digital matrix design lighting on US roads today could be turned on to provide greater visibility and less glare which means safer roads for all.”
SAE International, formerly known as the Society of Automotive Engineers, had earlier created its own standards for adaptive headlights through a committee of industry experts. NHTSA’s standards are more restrictive than SAE’s.
Safety regulations usually differ somewhat between different global markets. But, since adaptive beam headlights have been in use in other countries for a decade or more, automakers hoped that regulations would allow their introduction in this country without requiring major equipment changes, according to various industry sources.
“We had hoped it would have been a software change, and then it would have been rather quick to get the technology into the market,” said Michael Larsen, Technical Fellow for Exterior Lighting at General Motors and a member of the SAE’s lighting committee. “But when everyone started really looking at this complicated regulation, you just couldn’t get there from here.”
NHTSA’s rules require the ADB headlights to respond extremely swiftly after detecting another vehicle within reach of the lights, much faster than other standards require in the EU and Canada. Also much faster than a human could switch off an ordinary high beam headlight. They also dictate extreme narrow lines between bright and dark regions.
Ultimately, the NHTSA regulations require completely new headlamp designs for the US, Larsen said. This means the ADB capabilities engineered into headlights already on Audi and Mercedes cars in the US, for instance, will probably never get switched on.
Vision versus glare
The NHTSA regulations prioritize reducing any potential to cause glare for other drivers. Glare has been a particular concern for many years since new vehicles have brighter headlights that can sometimes cause discomfort or even temporarily blind other drivers. Many in the industry say the regulations overemphasize that concern, though, holding adaptive beam headlights to even higher standards than regular headlights when it comes to glare reduction.
“We should be focused on what we can do to improve visibility,” said Matt Brumbelow, a senior research engineer at the Insurance Institute for Highway Safety. “We know that low visibility causes crashes and what ADB does is maximize visibility, seeing light, while still preventing glare.”
The US regulations also limit the amount of light the headlights could put out while also not allowing them to reduce lighting as much they could in other situations, said Brumbelow.
“[We could] reduce glare compared to a high beam, and even lower than what a current low beam would be,” he said, “but we can get more light out there everywhere else.”
NHTSA declined to comment on the regulations beyond what’s written in the final regulation itself, which makes it clear that glare is a concern. NHTSA also states that other standards put forth by the industry, such as an SAE standard, don’t do enough to prevent the systems from sometimes putting too much light into the eyes of other drivers.
Eventually, ADB will come to the American roads but, assuming there’s no change to the regulations, it will take a while. One day, Americans will be able to use high-tech headlights that can do more than just make light shows.
Clarification: This story has been updated with the SAE’s new name.
