Veil Of Darkness

Just to explain how we got to headlights (halogen, HID and LED) having such a well-defined cutoff pattern, let's go back in history a bit. Remember sealed beam headlights? Believe it or not, they were a major improvement over everything that came before them as far as the amount of usable light they put out. They were also the first headlights to have federal standards applied to them relating to how much light they needed to / were allowed to put out and where it needed to go. That said, if you parked a 1960's vintage vehicle with sealed beams 25' away from a building wall and looked at the pattern, you would find a couple of fairly ill-defined blobs. But, it was better than what preceded them!

Next came polycarbonate (plastic) "aerodynamic" headlights with replaceable halogen bulbs. They actually appeared in Europe first because US lighting regulations didn't allow them. Eventually, the US woke up / caught up and the regulations were changed to allow them because they put so much more usable light on the ground. Bulb output was regulated by the maximum allowable number of watts for low and high beams. (Watts is not a measure of light output, but rather a measure of power consumption. In a classic incandescent bulb though, it's a decent proxy for output.) This change allowed lighting designers - and vehicle stylists - much more freedom and aerodynamics improved too.

With the change to replaceable bulbs - separate from the actual lens / reflector / housing, we started to see advanced optics such as the Cibie Z-Beam headlight which was one of the first headlights to utilize a horizontal cutoff. Why did they do this? Because if you couldn't use a more powerful bulb, maybe you could better distribute the existing amount of light. Obviously, you need most of the light on the ground in front of you, but you also need some light off to the sides to see road signs as well as above for the same reason. (I had a set of these in my 1976 Toyota Corolla Liftback and they were truly a breakthrough.)

But people still wanted more light. This led to things like HID (high intensity discharge) light sources. But these were so bright that conventional optics just led to tons of glare for oncoming drivers. (As many of us have noticed when idiots simply slap HID light sources in headlights designed for halogen bulbs.) Enter the projector headlight. Remember trying to stay awake while your neighbors showed you slides of their recent vacation - right after dinner? Remember how the slide projector lens - even without a slide - projected a perfect square of light on the screen? (I used to work for the Eastman Kodak Company and we made those projectors and the lenses, so I noticed that.) Somebody got the bright idea to try using the same technology in automotive lighting and the results were stunning. The problem was that lighting designers started to get a little bit too frisky with the cutoff and instead of a smooth transition from light to dark, they evolved into a hard cutoff line that some folks took as being better. Never mind that overhead signs were now all but invisible. (Hell, we had GPS for that, right?)

But HID systems were expensive, had lots of parts and did not come on full power instantly. (That's why many - but not all - HID systems were low beam only.) Enter the LED light source. Much cheaper to make. Way fewer parts, but just as much - or more - usable light. However, to properly harness and aim all of this light - and meet federal lighting standards - one needed to focus it properly. Once again, the infamous cutoff line came into play. But now, LEDs - with harsh cutoff lines - were available in almost every new car instead of just low volume / high performance cars and the average consumer had never experienced headlights with this "feature."

I remember my aunt calling me one day a number of years ago to complain about the headlights in her new Mazda - specifically the cutoff line - because as she drove down poorly lit / bumpy roads, the headlights appeared to jump up and down. Truth be told, they were not jumping up and down, but the cutoff line was. The same thing can happen when somebody with headlights with a sharp cutoff is driving towards you on a bumpy road. You'll swear that they're flashing their high beams at you, but in reality, you're just experiencing their cutoff bounding up and down with their vehicle.

So maybe, just maybe, the OP is experiencing just what I've described above. If so, there's not much that can be done to reduce the harsh cutoff in the factory headlights. The best option - other than trying to get used to it - is to add a set of auxiliary lights to supplement the low beams headlights. A "fog beam" won't work since it too is horizontal with a severe cutoff line by design. A "driving beam" won't work because you'll bother oncoming drivers. Hella use to make a model 550 "Mid-Beam" auxiliary light with just this purpose in mind. Unfortunately, they're no longer made - but guess what I have in my lighting stash?

 

You are not crazy, I just bought a 22 4Runner and took it out at night 3 days ago and I had the same problem. Some 4Runner ladies on Facebook said I might have a “brow tint”. But I don’t see it during the daytime. Did you ever solve this problem? I might bring it to the dealer but you can’t see it during the daytime!

 

Betting it’sthe “LED light line” described above. It’s really only visible in the dark. The darker the ambient, the more pronounced the “line”. It is pretty pronounced when you’re not used to it.
Got my attention.

 

OP hasn't come back since 2022. Looks like he was finally taken by the veil of darkness.