Good Headlamp - Engineer or Driver's Perspective?

Maybe some of you will like this.

Interesting - this basically amounts to support for auto-levelling, self-cleaning headlamps with consideration given to mounting height.

This makes perfect sense, as these rules are more or less already part of UNECE standards, aren't they? At least for high-flux lamps. I was shocked by the degree to which glare can increase with soiling.

What I've found disturbing seems to be the shift away from auto-levelling and self-cleaning headlamps. I know that the Lexus RX, for example, used to offer adaptive bi-xenon lamps with levelling and washers, but they got rid of some of these features at the refresh.

Similarly, I have an Accord Touring with excellent LED lights, but it offers neither cleaning nor levelling features. And it seems that's becoming increasingly standard.

The '09 and earlier [see page 9 of 31] aren't bi-projectors, but they do offer automatic [passenger rear sensor] leveling, with jack in the box type cleaners, and lateral acceleration cornering function [AFS in Toyota/Lexus speak]
The '10+ dropped the sprayers, added bi-HID, and don't remember about the leveling. (and changed from D2S to D4S)

Basically everything that is wrong with US lighting can be fixed by: adding mounting height to declination correlation. dynamic leveling for very high flux headilghts [front & rear sensors], automatic leveling for medium flux lights, and manual remote leveling [dial with 0-1-2-3, etc] for weak-sauce low flux lights.

MichaelW said:

Basically everything that is wrong with US lighting can be fixed by: adding mounting height to declination correlation. dynamic leveling for very high flux headilghts [front & rear sensors], automatic leveling for medium flux lights, and manual remote leveling [dial with 0-1-2-3, etc] for weak-sauce low flux lights.

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That's actually not quite true. The UN working groups on vehicle lighting regulations (GTB and GRE) are finally having the overdue discussion and doing the overdue research on the real effects on seeing and glare of headlamp leveling systems and lens cleaning systems.

"Overdue" because those measures were originally adopted on a "gentleman's agreement" basis back when the industry wanted to introduce HID headlamps. There was concern that they would cause unacceptable levels of glare (note: unacceptable, not necessarily unsafe), so to get HIDs onto the road an arbitrary threshold of 2000 lumens was selected; cars equipped with low beam light source(s) with total reference luminous flux more than 2000 lumens had to come equipped with static levelling and lens cleaning systems. Cars with less than 2000 lumens worth of low beam light source(s) had to come with manual (driver adjustable) leveling. At the time there was no research supporting any of this. Not the concept, not the implementation...nothing. It was purely political bargaining chips: the industry threw these "sounds like glare control" measures at the regulators, and the regulators said "OK", and everyone said they'd study the matter further.

Basing regulations for glare control on the luminous flux coming from the light source is...sorry, it's just stupid. Other drivers can't see how much light is coming from the bulb, they can only see how much light from the headlamp (i.e., the beam pattern) is reaching their eyes. It's very easy and extremely common to have a headlamp with a low-flux light source produce much more glare than a headlamp with a high-flux light source. Moreover, the leveling and cleaning systems cost money, and the cleaning systems take up a giant amount of space and add ill-afforded mass (in countries where a vehicle's CO2 emissions are an important factor in its marketability, taxation, etc).

The industry and consumers alike are working around the cost barriers these systems put up: the industry by producing 25w HID systems with rated luminous flux of exactly 2000 lumens (no leveling or cleaning system needed) and consumers by not opting for HID headlamp systems at new-vehicle purchase (too expensive).

Some very reputable European researchers are doing good quality research on just exactly how much effect these systems have on the real levels of actual glare from real cars to real drivers on real roads, and their findings are pretty predictable: Manual levellers are useless; nobody uses them. Static automatic levelling has no significant effect on glare because most vehicles are never rear-loaded to the degree that the headlamps' aim is significantly raised (that situation may be somewhat different in the US with heavily-loaded pickups and SUVs). Lens cleaning systems have some significant effect, but not a whole lot -- it's more a driver convenience/comfort factor (which is not to dismiss it lightly, but the data is showing a lens cleaning system isn't a "silver bullet" for glare).

Now, dynamic automatic levelling has a lot more promise, but it has to be a good-working system, and not all of them are. There's also some good American research (from UMTRI or LRC, I forget which at the moment) showing pretty dramatically that dynamic levelling works well to counteract beam aim changes during brake dive and acceleration squat.

Things would get much better if all vehicles had good dynamic aim systems on them -- and even better still if they all had the beam aim attainment system Porsche demonstrated not long ago, a camera-driven system that looks at the headlight beams and adjusts/corrects their basic vertical aim, rather than just maintaining whatever aim setting a (usually careless) human being set.

Eventually this will all be a problem of the past, as the "matrix beam" type fully adaptive systems do away with the concept of basic headlight aim, but that won't happen for a very long time.

Finally: No, even if we get to make a wish and have all cars come with dynamic levelling and self-aim, there's a fair amount more that needs fixing with US lighting. Still far too much allowance for bad/inadequate low and high beam headlamp performance. Still too low a cap on high beam intensity. Still no requirement for side visibility of turn signals. Still too many rear turn signal colors allowed. Still no effective regulation of fog lamps. Etc.

MichaelW said:

manual remote leveling [dial with 0-1-2-3, etc] for weak-sauce low flux lights.

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Except 99% of drivers will fiddle with that dial to what they think is the "best" setting. You can't trust them to make certain decisions correctly.

Scheinwerfermann said:

Other drivers can't see how much light is coming from the bulb, they can only see how much light from the headlamp (i.e., the beam pattern) is reaching their eyes. It's very easy and extremely common to have a headlamp with a low-flux light source produce much more glare than a headlamp with a high-flux light source.

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So much THIS ^

...there's a fair amount more that needs fixing with US lighting. Still far too much allowance for bad/inadequate low and high beam headlamp performance. Still too low a cap on high beam intensity. Still no requirement for side visibility of turn signals. Still too many rear turn signal colors allowed. Still no effective regulation of fog lamps.

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And THIS ^

Of all these, the turn signal issues (both side visibility, and too many (I'd say, ONE too many) colors for rear turn signals allowed) would be the top of my list. Turn signals are used whether it's day or night, raining or clear. Fixing turn signal issues would go a long way towards improving roadway safety.

MichaelW said:

and manual remote leveling [dial with 0-1-2-3, etc] for weak-sauce low flux lights.

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Alaric Darconville said:

Except 99% of drivers will fiddle with that dial to what they think is the "best" setting. You can't trust them to make certain decisions correctly.
.

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^this !

We have a few new Toyota Corolla "pool cars" at work that everyone shares, and they have that little 0-1-2-3-4-5 rotary switch.
nearly every time I get into one, it's headlights are adjusted down so far that there is a little puddle of light on the road, and the high beams have a coverage similar to what the low beams should be doing.
the headlights are actually quite good (in my opinion, better than the Camry, about equal with my Subaru, and not quite as good as the Kangoo van**) when adjusted properly.

On a completely unrelated note, it is typically when I have to adjust the seat from its forward-most position that I find this - either it's someone bumping the dial with their knee (it's down on the right hand side of the steering column) or someone with no idea about what the dial does "oh it makes the lights brighter, let's leave it at 5" and reducing their seeing distance to unsafe levels (seriously, at "5" the low beam looks like a very narrow fog pattern, lots of light in front of the car) and not much else

** I am aware that these are subjective impressions, with no real basis in science, however;
I feel the Camry lights are a bit dim
My Forester has good low beams, and good high beams, although they don't reach out far enough into the distance
And the horrendously awful to drive Renault Kangoo van has brilliant lights, low beam is like a panoramic picture of the road, with a cutoff that gently fades away, high beam is the same, but just gets rid of the cutoff and reaches out into the darkness.
i absolutely hated the Kangoo, until it got dark and I was driving it on unilluminated country roads.