I drive a sedan. Lately, I find oncoming headlights on new SUVs very bright. It’s like looking into high beams. Are headlights really getting brighter? Is it because more headlights are LED now? Is there a limit to how bright they can be? – David
LED, or light-emitting diode, headlights put out more light and are more intense compared with older technology such as halogen and high-intensity discharge (HID) xenon lights, experts say.
“[They] can show the driver more things not to hit, but it also means other road users' eyes are more likely to be within a high-intensity area of any vehicle’s beams,” which causes glare, says Daniel Stern, a Vancouver-based lighting consultant and chief editor of Driving Vision News, a technical journal.
Stern says headlights are “surprisingly complex” and aren’t 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 specific minimum – or maximum – allowed intensity of light.
The Canada Motor Vehicle Safety Standard (CMVSS) 108 is similar to regulations in the United States.
So, for low beams, the brightest light must be pointed at the right side of the road just below the horizontal and there are limits on how much light can point directly at the oncoming driver, Stern says.
The regulations are designed to let drivers see as far ahead as possible with their headlights without blinding other drivers on the road.
They apply to new cars coming out of the factory, but as they drive on the road, the factory-set aim can get thrown out of adjustment by normal driving, says Stern.
That means the brighter points of the low beam meant for the road may hit an oncoming driver’s eyes or the rear-view mirror of a driver in front, says Matthew Brumbelow, a senior research engineer with the Arlington, Va.-based Insurance Institute for Highway Safety (IIHS).
“There are still a lot of vehicles on the road that are missing aim,” Brumbelow says, noting that an increase in LED-equipped SUVs and pickups on the road, which have higher headlights, will increase the glare for standard vehicles.
Canadian and U.S. regulations allow for headlights to be mounted higher compared to regulations in the rest of the world – but the higher-mounted headlights must be aimed the same angles as headlights on a car.
Why? “Because that’s the way it’s been for many years,” Stern says. “If the lamp height limit were lower, automakers might have to redesign their trucks and SUVs.”
So that means, if you’re in a sedan, the brighter parts of even properly aimed headlights on an oncoming SUV or truck could be pointed at your eye level because their headlights are higher, Stern says.
Properly aimed lights could also suddenly point at your eyes if the oncoming car goes over a bump, for instance.
Glare can be worse if headlamps are dirty or crusted with ice, Stern adds. And heat goes toward the back on LED lights so ice and snow can build up on the lenses, causing glare until it gets thick enough to block light entirely.
While it’s possible for drivers to get their headlight aim checked and adjusted, it’s not easy to find a place that will do it, Stern says.
“Most shops won’t have the equipment to do the job,” he says.
Does brighter mean safer?
LED headlamps are also getting smaller and more blue and there’s “sturdy science” showing this can also worsen glare, Stern said.
“Any given amount of light coming from a smaller lit point will look brighter than that same amount of light coming from a larger lit area,” he says. “It’s called luminance, and while North American regulations limit the luminance of brake lights to control glare to drivers stuck behind them in traffic, there are no limits on headlamp luminance anywhere in the world.”
LED headlights are “overwhelmingly predominant” in new vehicles and all LED headlights are bluer than all headlamps with previous types of light sources, Stern says.
Blue-white light can worsen glare by more than 60 per cent compared to warmer light of the same intensity – and “there is no better seeing with the bluer light,” Stern says.
Plus, LED lamps flicker and, even though that’s not usually discernible to the naked eye, that also worsens glare, he says.
While there are safety concerns with misalignment, Brumbelow says the newer, brighter LED headlights make roads safer.
He says vehicles with better visibility from their headlights are involved in fewer nighttime crashes.
“And something to keep in mind is that just making everything dimmer will probably increase crash rates over all.”
In 2016, when IIHS started testing headlights on new cars for driver visibility and level of glare for oncoming drivers, only one out of more than 80 headlight systems was rated good.
In 2024, 44 per cent of systems (some car companies offer various headlights for the same model, depending on the trim) were rated good.
In a 2021 IIHS study, cars with good ratings had 19 per cent fewer nighttime single-vehicle crashes and 23 per cent fewer nighttime pedestrian crashes than vehicles with poor-rated headlights.
End of daze?
So glare can be annoying to other drivers, but is it dangerous?
While LED lights may not be the direct cause of vehicle crashes, Stern says they could be a factor if a driver is fatigued, distracted or panicked by glare from oncoming vehicles or in their rear-view mirror.
Stern says while Canadian and U.S. regulations don’t mention glare at all in their specifications for low beams, European regulations have stringent provisions to limit glare.
“[European regulations] sacrifice some seeing distance on low beams in order to have better glare control,” he says, adding that there will always be some glare.
He says years of research has yet to show that approach – prioritizing visibility or prioritizing glare control – is better for overall safety.
Car companies have developed technology to tackle glare, including high-beam assist, which automatically dims high beams as oncoming vehicles approach, and adaptive driving beams (ADB), also known as adaptive headlights, which use cameras to see other vehicles on the road and dim the specific parts of the headlight beam aimed at other drivers' eye-level.
While ADB has been allowed in Europe for more than 15 years, the tech has only been allowed in Canada since 2018. The U.S. has allowed ADB since 2022, but the U.S. rule “hamstrings the manufacturer” because it doesn’t allow sections of the light to be fully dimmed out, IIHS’s Brumbelow says.
Still, Stern notes ADB works well on country roads and highways, but not in busy traffic – for example, on Commercial Drive in Vancouver or Bloor Street in Toronto – “because there are too many cars around for the system to do what it’s supposed to do.”
One solution that could potentially help is to have headlights that could automatically keep their aim.
“Cost-effective technology exists … to actively attain the correct setting automatically,” Stern says. “It has to be engineered into the headlamps from the start. But it’s not required, so no vehicles are equipped.”
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