The new LED car headlights (especially seen on luxury cars) are universally awful: distracting, blinding, and wreck your eyes’ adaptation. When they show up on a tall vehicle like an SUV it’s even worse.
Headlight brightness is somewhat of a balance, between blinding oncoming traffic and not being able to see far enough ahead. Dark adaptation has its limits.
(AFAIK it's actually HID lights which make up most of the ridiculously bright headlight market.)
I'm amazed the trend in obviously too dazzling headlights has been allowed to get this far. I recently heard some industry expert defending them on the BBC saying, without a hint of irony, that they weren't brighter, they just looked brighter.
There's regulation that says they can't go above a certain threshold, so I'm inclined to believe it. Other things:
- The illumination is much more even and filling modern headlights literally cut an evenly lit polygon of light in 3d space, in old times it was much more raw and uneven. When coming into view, as your eye passes the edge of the light cone it receives the whole of it at once whereas previously the gradient was much more progressive. IOW they never go above the lumen cap, it's just even across the light port (thus indeed emits more candela) and falling like a cliff at the edge instead of decreasing towards the edge from the center.
- The light emitted is much more blue, which is harsher on the eyes, and even more so at night. As a most probably unintended effect this might help in combatting sleepiness, a sort of reverse f.lux, but too much and it's tiring and agressive. Try lighting up a 40W 2700K vs a 40W 6000K when going to the bathroom at night: the latter is harsh and blinding, even though they emit exactly the same amount of light.
Some old cars I've driven had yellow headlights and it was a pain to see anything, some semi-recent cars have 6000K and I hear aftermarket goes to 8000K which is beyond ridiculous. My car has 4200k stock HID, ballasted lights†, and I feel it's a nice, safe balance for everyone.
† ballast means their height auto-adjust so as to always be below eyesight of a crossing driver.
Having bright blue headlamps makes it harder to see into the shadows even for the car’s driver, because it causes the eyes to be less dark-adapted. Older halogen lamps work better in practice. The newer LED lamps only sound better in marketing materials, and based on junk metrics created by the industry itself.
The problem is not LEDs inherently, but the spectral power distribution and excessive intensity of the specific “white” LEDs on the market, whose light comes from a blue LED and not enough of which is absorbed by the yellow phosphor.
If cars switched to LED headlamps with a CCT of 2700 K or the like, they’d be much less objectionable.
I’ve taken to wearing orange safety glasses when I walk my dog at night and sometimes when I drive at night, so that the combination of street lamps + car headlamps doesn’t delay my sleep and cause bright-adaptation of my eyes. But I would really rather not be forced to take such dramatic and somewhat unpleasant countermeasures.
There are definitely some ridiculously bright LED lamps driving around my neighborhood, as is easy to confirm by looking at them through diffraction grating glasses.
Headlight brightness is somewhat of a balance, between blinding oncoming traffic and not being able to see far enough ahead. Dark adaptation has its limits.
(AFAIK it's actually HID lights which make up most of the ridiculously bright headlight market.)