New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1917-03-18

GUS complaint of the erect OF Slaie'
said Mr.. McMurtry. "The second stage
came with the shifting of the driving
position from the right TO the left side
of the car. Then automobile drivers
we're themselves subjected to serious
inconvenience, not TO say danger, be-
cause they remained IN the beam Of re.
flected light thrown by the head lamps
of approaching cars for much longer
time than before" The third or cul-
minating stage was reached with the IN
PRODUCTION of the nitrogen type OF bulp'
with its concentrated filament OF great
intrinsic brilliancy, which caused the ell
feet of glare not only to all drivers out
to all users of the highway.
The comparison of the two antl-glare
methods was thus stated:
Diffusion Method
Advantages:
/. Focusing not necessary.
2 Aiming of lamps not important
g. Sufficient light close 10 and at sides OF
car.
Disadvantages:
/, Determination az TO the amount OF glare
most difficult.
.. Glare varies with change in voltage.
dlepower ia used.
4. No distant illumination of road.
3. Effect Of glare greatest near the car.
6. No warning beam in advance OF car.
DETECTION McthoS
Advantages:
I. No expense TO tilt lamps.
.. Distant road illumination excellent.
3. No glare whatever near car.
4. Most efficient light distribution on road.
bod of ~
ance with reasonable ordinance.
G. Temporary changes in voltage or in
candlepower of bulb do not cause
change in glare, provided bulb is
properly focused. There ia practical
ly no limit TO amount OF light that
can be used safely so long as 1t Il
kept below the 42-inch limit
= Warning beam can be seen many feet IN
advance Of car. and helps TO reduce
contrast between approaching head
lamps and roadway.
S. The height OF a beam OF light can be
absolutely determined in the daytime
by looking into the lamps from a
point ahead of the car and adjust
ing them that the reflected light
does not strike the eye when the latter
is more than ~ inches above the
ground.
Disadvantages
|. Exact focusing necessary.
.. Causes momentary glare when car Is
passing over top of hill or extremely
rough or uneven roads.
The confusion incident TO the prob
lem of regulating glazing headlights is
caused by the attempt to discover a
method or means for the absolute
elimination of glare without reducing
to any appreciate extent the road IL
Elimination" said Mr.. McMurtry. This
is practically impossible. as the ultl-
mate solution of the problem must re-
suit in a compromise between the value
of the road illumination and the glars
ing effect produced by the lamps.
For instance. if the diffusion prin-
clple is adopted there cannot be suf-
ficient illumination on the road with
out causing disastrous glare effects
when near the car If the detection
principle is adopted certain amount
of momentary glare, due TO the position
of the car, must be permitted in order
to gain the advantage of proper road
illumination, while at the same time
(by limiting the height of the beam of
Light preventing the effect of glare
probably over IS per cent of the time
the head lamps are in use.
'ln suggesting any means for glare
reduction which may possibly be adopt
ed in future laws another thing must
be remembered the effectiveness of
the law depends upon the manner in
which il can be enforced by the aver
age officer Therefore simplicity OF
regulations is much 20 be desired. The
simplest method Of determining glare
reduction will be most effective be-
cause of the greater probability OF uni
versal enforcement.
b.. IL,
plicity and freedom from highly tech
meal requirements, it is unwise 10
allow regulations TO drift into vague
ness or ambiguity. The motorist
wants to know precisely the limitations
ton of complying with the law he
also wants the best road illumination
the law will permit. A source of light
of one candle power will cause the
effect OF glare II of sufficient intrinsic
brightness Therefore the specification
must not glare or dazzle Is most
vague. Until we have standard unit
of glare measurement we must not toll
crate such vague requirements.
1.-THE principle of the limitation OF
light zone has been Endorsed by various
organizations. including the Society OF
Automotive Engineers. IL is the most
effective from the motorists point OF
view because it reduces glare with the
least loss of useful light, and in most
applications il creases the amount OF
light upon the roadway.
at is the method most readily Gov
cred by simple and easily understood
ordinance. an ordinance which is not
only effective in accomplishing the de
sired result. but with which il is easy
TO comply and which II is correspond
inglv easy to enforce. When once
properly applied any change of voltage
or candlepower Of bulb providing
proper focus is maintained) does not
alter its effectiveness. Bulbs OF nj
nest any candle power may be usec
without altering in any way the ligh
distribution or glare reduction.
Unlike the diffusion method. there
is less glaring light near the car, an'
| this il an important item where TIVE
cars are passing on narrow road
! Limiting the light zone will not, how
ever, prevent glare when the car u
passing over an uneven road, or owe
the top of a hill.
zone of the greatest factors Of ssfet.
| in night driving is the projection o
light some distance in front of the car
' II acts a. warning to others approach