This post of Keith's deserves to be preserved, along with the complete
version of the one it replies to, in the Keith Hall of Folly. It
displays so many of his flaws.
On May 15, 9:11 pm, "Keith F. Lynch" <k...@KeithLynch.net> wrote:
> ppint. at pplay <v$af$
pp...@i-m-t.demon.co.uk> wrote:
>
> > - this is enough to make the transition effectively impossible, even
> > if the glare problems of non-car and lorry road-users are ignored.
> > the glare drivers using the ultra-bright, blue-white halogen
> > headlamps cause other users (and themselves in heavy snow and fog)
> > is bad enough, the dazzle temporarily blinding drivers of oncoming
> > vehicles ...
>
> I'm not convinced. Headlights are as bright as they are today mainly
> to compensate for the dazzle from oncoming headlights. It's an arms
> race, one that nobody can win. Remove the dazzle, and headlights can
> all get a lot dimmer and yet serve their purpose better than ever
> before.
Here's something Keith should know better than to do. He makes a flat
assertion on a subject in which he has very little experience (driving
cars at night) to an audience full of people well experienced in the
subject.
How many drivers here were aware that there was a was an arms race
between ourselves to put in brighter headlights? None? I thought so.
Only in Keithworld is this true. I use my headlights to see the road,
often in conditions where there are no other cars. Dazzle from
oncoming cars simply isn't a factor. It's annoying when it happens,
but almost never a serious problem.
> As for non-motorists -- of which I am one -- they can wear polarized
> glasses or clip-ons. In busy areas, there's more than enough light to
> see by even if half of it is blocked. In less busy areas, there isn't
> enough oncoming traffic to worry about, so there's no need for such
> glasses.
90+% of the time when walking around at night, you're *not* dealing
with dazzle, even in the city. But Keith want everyone to diminish the
light available to see by by 50%. I'm not that stupid. I don't think
most people are. Here Keith is creating a serious problem to solve a
trivial one.
> > add to this the cost of converting - or junking - all cars' lorries'
> > and bikes' head, turn indicator, rear, stop and fog lights, all
> > front, rear and front passenger windscreens and windows, all bikers'
> > helmet visors & goggles, and all cycles' lights systems ...
>
> There's no need to convert bicycle headlights, as those have never
> been especially bright. They're mostly meant for being seen, not for
> seeing.
Keith is a city boy. I've ridden bikes many times when the bike
headlight made the difference between being able to ride, and having
to walk. Not everyone is Just Like Keith.
Neither is there any need to convert turn indicators, brake
> lights, or anything else that isn't dazzlingly bright.
>
> The conversion is easy, as it just consists of adding a polarized
> filter.
Except they'll all now be half as bright.
> Contrast this with the oft-repeated claim that it's necessarily to
> completely replace *all* computer equipment and peripherals, and
> every cell phone, every two or three years, forever. And to replace
> them with completely incompatible equipment with different user
> interfaces.
This may happen on Keithworld. I'm glad I don't live there.
> > ..and providing suitable polarised glasses for the entire population
> > to wear whilst cycling or walking along roads at night...
> Yes. So? Do you think that's beyond the industrial capacity of the
> US or the UK?
Wearing sunglasses at night is dumb, even if it saves you from having
to shade your eyes against the occasional car. Keith is creating a
serious problem to solve a trivial one.
> > (would it be a legal offence to cycle at night without wearing these
> > essential protective wear against driving whilst dazzled? to walk
> > about on public roads at night, likewise? horse-riding?)
>
> Of course not. Since headlights would be dimmer, dazzling would be
> less of a problem. They would be available for those who want them.
As explained, headlights would actually become brighter, not dimmer.
Keith's imaginary brightness arms race is just that - a self-
justifying fantasy.
> Those will probably mostly be people who who live in built-up areas or
> who are especially sensitive to glare.
>
> As for seeing oncoming vehicles, polarizers aren't 100%. Oncoming
> headlights would still be easily visible, they just wouldn't be
> blindingly bright.
>
> As for the mention of polarization being scrambled by the road
> surface, I don't think so. It isn't scrambled by movie screens,
> otherwise 3D movies that rely on polarized glasses wouldn't work.
> Why would roads be any different?
They're different, because roads aren't coated in silver or aluminum,
as the screens that are used for 3d projection are. Specular
reflections off metal don't lose much polarization. Diffuse
reflections, as off of asphalt, do. As Wikipedia says: "Polarized
light reflected from an ordinary motion picture screen typically loses
most of its polarization, but the loss is negligible if a silver
screen or aluminized screen is used."
Of course, Keith, in his studied ignorance, doesn't know this.
> What's the alternative? The current arms race isn't working, even if
> you totally ignore the big losers in the lumen game -- pedestrians and
> cyclists. Everyone can't have brighter headlights than everyone else.
There isn't an arms race, and there are legal limits on headlight
brightness. Newer systems are a lot better than they used to be; the
upper cut-off of the beam is far better defined.
> There have long been eyeglasses that darken in response to bright
> light. Is it possible to have eyeglasses that darken in response to
> bright light in just one direction, and which do so very quickly?
Yes. The rearview mirror in my car does this.
Finally, note that Keith carefully cuts out the point that there are
legal limits to windscreen tints, which his proposal violates. He
doesn't actually have any way to reply to it, so he pretends it didn't
happen.
pt