In some European countries there are regulations for bike lights, some even require cut-off beam like Germany. However in US the front light is dual purpose - it's illuminating the road at night and keeps salmoning bikers/runners/electric motors enthusiasts from running into you so a cut-off beam is counter productive for this purpose.

I've experienced the same problem with newer car headlights, which despite being regulated are now far too bright and concentrated, creating a very bright and very dark region with a sharp line between them instead of the dimmer but more diffuse gradual cutoff they used to have. Eyes have dark adaptation so you can see farther with the latter, and it's also better for oncoming traffic.

Much of that (I'd like to say most) is due to a bad beam pattern and/or improper aiming.

For instance: Round beams suck. The first LED front light I ever bought was nothing more than a flashlight that took 3 AAA cells and attached to a handlebar mount.

It produced a round beam. If I aimed it up/far enough ahead that I could see the road ahead in any meaningful capacity, then it was also blinding to other riders and people in cars.

I could aim it down some and limit others' exposure, but then it was useless at letting me see what I needed to see, myself.

The most recent front light I have came from Walmart, and was sold in Schwinn packaging. It's rechargeable. With this light, other people have zero direct exposure to the LED because it is occluded by the housing.

It uses optics to shape the light. A curved mirror, and AFAICT a lens are inside. The beam it produces is shaped to evenly illuminate my path and it has a very sharp horizontal cutoff.

It's a very sensible design, in that when I aim it at the road so I can best see, other people's eyes are above the cutoff so they aren't blinded by glare. Everyone wins.

But not every bike light has a sensible design. And not every rider has sensible intent.

(The Germans have standards for this stuff enshrined in StVZO, wherein: Stuff like beam shape and cutoff is governed by law. Searching for StVZO lights tends to yield good results.)

It might be complicated.

It is indeed unregulated and often blinding. But there is also no one limited use case as it can be for car lights:

- these lights are sold internationally so they don't assume one specific country in the first place

- it's not just for road use, people will use them in rougher bike paths where there might be absolutely no other light.

- seeing the path forward isn't often enough. You don't have a windshield nor can assume a cleared path, so knowing what's at head level can also be crucial. Even on dedicated bike paths there will be branches and unmaintained/unexpected bits that need avoiding.

- being seen can be as important as seeing yourself, and often back lights are small and a pain to recharge. Many customers will want a wide spread front light that reflect all around, even if it mean charging it more often etc.

All in all, it might be that biking itself is wholly unregulated so lights will have a hard time being single purpose and regulated as well.

Ok, so only loosely related - I find new matrix headlamps on cars to be pretty intriguing. Basically they have an array of lights that are focused like pixels, and they can turn off the pixels that would blind others.

Wonder if this kind of stuff can trickle down to bicycles and motorcycles and you only light what's important in front of you. This could be to light more stuff so you can see it, or less stuff and save power while seeing what's important.

That seems like an intentional design choice as truly unregulated LEDs without even ballast resistors will burn out.

It's probably this way because companies design products to cater to their customers, who would likely prefer a Damn Bright Light to feel like they got their money's worth.

It's not a brightness thing, after all car headlights are probably 1000x brighter than anything you may have on your bike.

It's because 99% of bike lights are basically just flashlights, spraying light everywhere. The solution is the same as for cars — lights with horizontal cut-offs.

I also hate flashing lights. Is it just me or do flashing bike lights cause some kind of strange mild disorientation? In addition, they are distracting and stop me seeing other things.

Probably depends on jurisdiction. E.g. in the UK there is no formal limit (and car headlights are more powerful than bikes') but light must not dazzle or cause glare to other road users, hence why headlights on full beam must only be used in certain circumstances, and beams in general must have specific orientation.

So if you are blinded by an incoming cyclist this is not legal... of course enforcement is another matter.