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Comment by djoldman | Hacker News Reader

> Chris Trechter, a lighting-focused engineer who used to work for Magna International, the largest automobile parts manufacturer in North America, told me the company would adhere to 108 in making headlights for clients like General Motors but that the rule is “archaic.” “It does not account for LEDs,” he said, “and there are giant loopholes that allow you to throw basically unlimited light as long as you meet all the other aspects of 108.”

There are multiple references to this idea that you can have a basically unlimited brightness headlamp because the way it's tested is flawed. Anyone know how the testing process works?

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They measure at a certain point. Jason Cammisa points it out pretty clearly in an episode of Carmudgeon, with the money quote either here[0] or in the link direct to YouTube here[1]:

> On a recent episode of the Carmudgeon Show podcast, auto journalist Jason Cammisa described a phenomenon occurring with some LED headlights in which there are observable minor spots of dimness among an otherwise bright field of light. “With complex arrays of LEDs and of optics,” he said, “car companies realized they can engineer in a dark spot where it’s being measured, but the rest of the field is vastly over-illuminated. And I’ve had now two car companies’ engineers, when I played stupid and said, ‘What’s the dark spot?’ … And the lighting engineers are all fucking proud of themselves: ‘That’s where they measure the fucking thing!’ And I’m like, ‘You assholes, you’re the reason that every fucking new car is blinding the shit out of everyone.’”

[0] https://www.theringer.com/2024/12/03/tech/headlight-brightne...

[1] https://youtu.be/MkwjMV2of_8?t=697

https://news.ycombinator.com/item?id=42332716

It sounds like there is an area that is focused on for the test and they can engineer the lights to avoid putting too much light in that area.

Casually newer GM vehicles are one of the worst offenders together with Tesla with their poorly-shaped light beaming, that’s maybe a cosenquence of having a front end in the vehicle so high that the the headlights are level with the roof of “normal” sedans.

tbf newer Teslas all have matrix LEDs but they aren't enabled in the US because of NHTSA. I bet it's just a feature flag suite away too.

What's a matrix LED?

A technical kludge around drivers who refuse to dip their hi-beams by creating a dynamic mask around other vehicles - matrix LED headlights act as a bright, low-resolution projector that keeps other vehicles unlit, but lights up everything else.

How is getting all of the advantages of high beams without the blinding factor of other drivers a kludge? It’s a huge benefit. Auto high beams already exist.

> How is getting all of the advantages of high beams without the blinding factor of other drivers a kludge?

Because it's not just other drivers inconvenienced by super bright lights - people in their homes, pedestrians out if sensor range and camera systems are unaccounted for. Also, because a simpler solution exists for 99% of the times drivers abuse high beams, and has existed for 50+ years.

Driver ed books in most jurisdictions spell out where high beams ought to be used, and well-lit city streets are not one of them. It's kludge because it's being offered up as a technical solution to make up for rule-breaking drivers who use high beams as an default-on, when they ought to be default-off. Don't use high beams unless you need them, which should be a minority of the time. The bulk of society seems to have decided not to be inconvenienced by only seeing 20 car lengths at night, screw everybody else's night vision.

This sounds like a failing of the system to not dip the high beams in the presence of sufficiently bright street lighting. I'm not sure how mandating matrix headlights be not used is the solution here.

My auto high beams don't come on at all during city driving that is reasonably well lit, since its detecting something to cause them to dip.

> I'm not sure how mandating matrix headlights be not used is the solution here.

That's not what I'm suggesting at all - matrix headlights absolutely should he used - clearly some drivers "need" them, I'm just identifying them as a kludge for asshole drivers who can't be bothered to flick a finger or thumb to dip their lights.

Again, how is it a kludge? If you want to argue standard 'auto' high beams are a kludge, then maybe... but matrix headlights are performing a function that is literally impossible by a driver. Having high beams still illuminate an area where no cars are is strictly better, especially on the proper locations where it should be used (poorly lit rural areas), and there is no way to do that without matrix headlights.

The current Rivian cars have this, enabled, in the US.

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