[ROVERNET - UK] LIGHTS and brains
KG at dolby.com
Wed Feb 14 21:36:03 GMT 2007
Unusually, I will jump in here with my pet hates. Normal headlights,
operated by daylight with good visibility (rain or no rain), do no good
whatever, but occasionally can be dangerous because they prevent one
from seeing something just beyond them, like a child stepping out behind
a car. California recently made it compulsory to turn on the headlights
when the windshield wipers were in use, irrespective of lighting
conditions; I wonder how many accidents have occurred as a direct
result. Proper low-intensity running lights are a different matter;
they may be innocuous but generally serve no useful purpose apart from
the profit to the manufacturer.
On the blue horrors, I am surprised that no-one has mentioned that for
many years in France it was compulsory for French-registered cars to
have amber headlights. Visiting vehicles did not legally have to
comply, but if the visitors didn't fit amber filters, French drivers
tried deliberately to dazzle them in return. The point is that the
dazzle was very much less; I remember from vacations how much better it
was to drive after dark in France than in say Germany. Alas, in
conforming to European Union standards, that safety feature was
abandoned; it ought to have been introduced in all EU countries.
Directly related, in my childhood, driving from London to Redhill in
Surrey, the street lighting for much of the distance was sodium
(yellow). Then there was a stretch of mercury (blue) and only then did
you discover that it was foggy!
Ken G, 1925 Rover 16/50 (San Francisco)
From: rovernet-bounces at lyris.ccdata.com
[mailto:rovernet-bounces at lyris.ccdata.com] On Behalf Of David Read
Sent: Tuesday, February 06, 2007 6:21 PM
To: rovernet at lyris.ccdata.com
Subject: Re: [ROVERNET - UK] LIGHTS and brains
Eric Russell wrote:
> The REAL trouble is the white light/blue light high intensity beams
> usually found on high end cars.
The reason blue lights dazzle more is that the shorter wavelength blue
light is scattered more by passage thru air, .... that's why the sky is
blue at midday, being filtered and scattered by the earth's atmosphere,
and orange at sunset since all the blue has been completely scattered
and absorbed by it's longer/oblique passage thru the atmosphere.
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