I drive a limousine. Lately I've found the oncoming headlights of new SUVs to be very bright. It's like looking into the high beams. Are the headlights really getting brighter? Is it because more headlights now have LEDs? Is there a limit to how bright they can be? –David
According to experts, LED headlights (light-emitting diodes) emit more light and are more intense compared to older technologies such as halogen and HID xenon headlights.
“[They] can show the driver more things they shouldn't hit, but it also means that other road users' eyes are more likely to be in an area of high intensity of a vehicle's rays,” which leads to glare, says Daniel Stern, a Vancouver resident resident lighting consultant and editor-in-chief of Driving Vision News, a trade publication.
According to Stern, headlights are “surprisingly complex” and are not just a single beam of light that can be made brighter by turning up a dimmer. He says they have wider beam patterns and are divided into specific points and zones. These zones have a certain minimum – or maximum – allowable light intensity.
Canada Motor Vehicle Safety Standard (CMVSS) 108 is similar to regulations in the United States.
So with low beams, the brightest light must be aimed at the right side of the road just below horizontal, and there are limits to how much light can be aimed directly at the oncoming driver, says Stern.
The regulations are designed to allow drivers to see as far ahead as possible with their headlights without dazzling other drivers on the road.
They apply to new cars that leave the factory, but while driving on the road, the factory-set destination can get out of control through normal driving, Stern says.
That means the brighter points of the low beam headlights intended for the road could hit the eyes of an oncoming driver or the rearview mirror of a driver in front, says Matthew Brumbelow, senior research engineer at the Insurance Institute in Arlington, Va. Highway Safety (IIHS).
“There are still a lot of vehicles on the road that miss their target,” Brumbelow says, noting that an increase in LED SUVs and pickups on the road that have taller headlights will increase glare on standard vehicles.
Canadian and U.S. regulations allow headlights to be mounted higher than regulations in the rest of the world – but the higher-mounted headlights must be aimed at the same angle as a car's headlights.
Why? “It’s been like this for many years,” says Stern. “If the lamp height limit were lower, automakers might have to redesign their trucks and SUVs.”
That means if you're sitting in a sedan, the brighter parts of even the properly aimed headlights of an oncoming SUV or truck might be aimed at your eye level because their headlights are higher, says Stern.
Properly aimed lights could also suddenly focus on your eyes when the oncoming car goes over a bump, for example.
Glare can be worse if headlights are dirty or caked with ice, Stern adds. And with LED lights, the heat travels backwards, so ice and snow can build up on the lenses and cause glare until they become thick enough to block the light completely.
While it's possible for drivers to have their headlights' alignment checked and adjusted, it's not easy to find a place that does this, Stern says.
“Most repair shops don’t have the equipment to do this job,” he says.
Does brighter mean safer?
LED headlights are also becoming smaller and bluer, and there is “robust science” showing that this can also lead to worsening glare, Stern said.
“Any amount of light coming from a smaller illuminated point will look brighter than the same amount of light coming from a larger illuminated area,” he says. “It’s called luminance, and while North American regulations limit the luminance of brake lights to prevent blinding drivers behind them in traffic, around the world there are no limits on the luminance of headlights.”
LED headlights are “predominantly prevalent” in new vehicles and all LED headlights are bluer than all headlights with previous types of light sources, says Stern.
Blue-white light can worsen glare by more than 60 percent compared to warmer light of the same intensity – and “you don't see better with the bluer light,” says Stern.
Additionally, LED bulbs flicker, and while it's usually not noticeable to the naked eye, it also makes glare worse, he says.
While there are safety concerns with misalignment, Brumbelow says the newer, brighter LED headlights are making the roads safer.
He says vehicles with better visibility from their headlights are less likely to be involved in nighttime accidents.
“And you should keep in mind that if you make everything dark, the overall crash rate is likely to increase.”
When the IIHS began testing headlights on new cars in 2016 for driver visibility and levels of glare to oncoming drivers, only one of more than 80 headlight systems received a “good” rating.
In 2024, 44 percent of the systems (some car manufacturers offer different headlights for the same model depending on the equipment) were rated good.
In a 2021 IIHS study, cars with good ratings had 19 percent fewer nighttime solo accidents and 23 percent fewer nighttime pedestrian accidents than vehicles with poorly rated headlights.
End of the daze?
So glare can be annoying to other drivers, but is it dangerous?
While LED lights may not be the direct cause of vehicle accidents, Stern said they could be a factor if a driver becomes tired, distracted or panicked due to glare from oncoming vehicles or in the rearview mirror.
Stern says while Canadian and U.S. regulations don't mention glare at all in their low beam specifications, European regulations have strict provisions to limit glare.
“[European regulations] With low beam headlights, give up a certain viewing distance for better glare control,” he says, adding that there will always be some glare.
He says years of research have not yet shown this approach – prioritizing visibility or reducing glare. is better for general security.
Automakers have developed technologies to combat glare, including High Beam Assist, which automatically dims the high beams as oncoming vehicles approach, and Adaptive High Beams (ADB), also known as adaptive headlights, which use cameras to detect other vehicles on the road and dim them certain parts of the headlight beam aimed at the eye level of other drivers.
While ADB has been permitted in Europe for more than 15 years, the technology has only been permitted in Canada since 2018. The US has allowed ADB since 2022, but the US rule “hinders the manufacturer” because it does not allow parts of the light to be completely dimmed, says Brumbelow of the IIHS.
Still, Stern notes that ADB works well on country roads and highways, but not in heavy traffic — for example, on Commercial Drive in Vancouver or Bloor Street in Toronto — “because there are too many cars on there for the system to do that could do what it's supposed to do.”
One solution that could potentially help would be to use searchlights that could automatically hold their target.
“There are cost-effective technologies for actively and automatically achieving the right setting,” says Stern. “It has to be integrated into the headlights from the start. But it is not required, so no vehicles are equipped.”
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