Blinded by your lights: In a battle to see, why are blinding headlights winning?

There are three types of headlights: tungsten-halogen, Xenon high-intensity discharge (HID) lights and light-emitting diodes (LED).Willowpix

If there is one thing drivers hate, it's not being able to see while driving. There's something about being able to see and then suddenly having your vision blasted by a fiery shaft of blue light that's a turn off. I occasionally receive e-mails from readers lamenting this fact. In late December, I received another. "How about [a column] focusing on the blinding intensity of newer headlights?" wrote Kirk. "Some are so bright, I’m left wondering if the oncoming driver is trying to see into tomorrow."

Kirk is right. As I write, countless drivers are screaming a series of expletives as they stare into headlights so bright that they leave drivers feeling as if they’ve just opened the Ark of the Covenant.

While the headlight versus "being able to see" battle seems modern, it's been waged since the introduction of automobiles and most likely began in 1915, when Cadillac introduced low-beam headlights that drivers had to adjust manually after stopping their vehicles.

Today, we have three types of headlights: tungsten-halogen, Xenon high-intensity discharge (HID) lights and light-emitting diodes (LED). Introduced in the 1980s, halogen are the cheapest. Xenon (which were not named after the Bally 1980 pinball game) were introduced in 1990s. These create light by passing electricity through xenon gas. They produce three times the illumination of halogen lights, but HID's signature blue hue does not trigger a strong reflexive pupil-closing reaction. The eye is left more open and vulnerable to searing glare. The automobile industry "solved" this problem by creating LED headlights, which became popular in the 2010s. LEDs don't produce a lot of heat or drain the car battery, have long lifespans and are around 275-per-cent brighter than halogens. That said, LED should stand for "Legally Eye Damaging."

A 2022 study of 2,700 drivers conducted by RAC, a British automotive services company, found 89 per cent of drivers think "some or most car headlights on the U.K.'s roads are too bright, with an overwhelming majority of these 88 per cent saying they get dazzled by them while driving. In December, Transport Canada recalled 85,685 GM cars, SUVs and trucks because their "daytime running lamps that stay on could cause glare for oncoming drivers and increase the risk of a crash."

According to ABC 8News in Richmond, Va., a politician wants a statewide ban on blue headlights. "Senator Lionell Spruill (D-Chesapeake) submitted the legislation ahead of the General Assembly's January session. The law would ban all car modifications designed to make headlights ‘appear as a blue light, such as by covering the headlights with a tinting film or by using blue bulbs.’"

Why do drivers feel more blinded than ever before? While LED-lovers argue that properly installed LEDs should not be blinding, there are aspects of the LED that lead to vision trouble. Put simply, HID (and more specifically LED) headlights emit far more blue light than halogen lights. "The problem with LED headlights is that they are incompatible with dark adapted human eyesight," wrote John Lincoln for the England-based advocacy group Lightaware. "Particularly for older drivers – they are too bright, too blue, too ‘concentrated’ and blinding over too long a distance … the bluer spectrum of light from LED headlights disables the night adapted vision of the human eye to a much greater extent than that of conventional halogen headlights – pupil size is more strongly correlated to blue light than yellow light."

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Another factor is vehicle height. Jacked-up SUVs put their headlights blaring right at driver level. Add to this the reality that driving is done on a series of hills, flats and dips, and you get frequent bouts of brazen pupil-incinerating headlights.

Finally, LEDs cast focused directional light. An LED light is like a focused laser compared to more diffuse halogen light. If this light hits you directly in the eyes, it brings its full concentration. Hence the "do not go into the light" near-death experience.

How long will we have to be stunned by the glare of LED and HID headlights? Unfortunately, we’ll wait for the next advance the automobile industry has to offer. At the moment, this appears to be "advanced forward lighting systems" that automatically adapt to driving conditions and which, so the theory goes, also "adapt" to not blinding oncoming drivers. Given the fact that when LEDs were introduced, they were considered a solution to the blinding blue of HIDs, we can expect to be dazzled by "advanced forward lighting systems" too.

The war on blinding headlights has begun and, like most wars, it will never really end.