Los Angeles herald. [microfilm reel] (Los Angeles [Calif.]) 1900-1911, 1908-05-17
GOVERNMENT OFFICERS
EXPERIMENT WITH CAR
TEST EFFECTS OF SPEEDING
AUTO
Engineers Travel at Mile q Minute
Pace to Prove Theory That Rub
Der Tired Vehicles Ruin
RoadWays

| A twO-ton racing automobile NOV
ing at something in excess of mile
a minute while an Uncomfortable cloud
of fog-gray rock dust hung to the hor-
icon and marked the speeding course
of the big machine was the sight wit
messed by travellers on the famous
| conduit road dozen miles from
Washington on Thursday April 25s
The seemingly pronounced violation
of the speed ordinances was counte-
nanced by two of the nations federal
departments, agriculture and war;
however. the rushing motor car hay
ing been pressed into requisition by
L. w. Page, director of the office or
public roads. and DIR. Allerton S. Cush-
man, assistant director, in the effort
to determine the effects of automobile
traffic upon macadam highways. and
the stretch of thoroughfare was placed
at their disposal by war department
officials.
While the racing car and others of
various weights and types made many
trips over the selected stretch OF
mile and a half at varying rates OF
speed, from five to sixty-five miles an
hour, a corps of skilled photographers
equipped with the most modern de-
vices for photographing vehicles at
very high speeds, made accurate rec
Shorten Lives Of Surfaces
1t has long been known to highway
engineers that automobiles were rap
idly shortening the lives of the rock
surface roads of the world and many
experiments have been made in the
past six or seven years to determine
the actual causes of the damage done.
To understand how the soft broad
tires of the modern motor car can
work an injury to a surface that not
only wlthstands but improves under
the constant passing and repassing OF
vehicles with iron tires, one must be
apprised briefly of the theory on which
first Tresauget of Limoges and later
MacAdam of Ayr worked when giving
such highways to the world. They
reasoned that a road surfaced with
bits of stone would improve under
wagon traffic because the iron tires
of the passing vehicles would con-
stantly crush the stones and form
rock dust particles: that those rock
dust particles would not merely fill
in all the interstices between the stones
but would also form a surface dust
binder; the Wettings and rollings tend
ing to cement the dust into she'll
like surface and thus make the entire
road one traffic. understanding, water
shedding mass.
Reason Well
They reasoned we'll and wisely. The
mac adam roads lived up to the theo-
ries of their inventors and improved
with the passing years until the ad-
vent of the automobile. 1t was but
short time after it came into vogue
that highway engineers in all civilized
lands learned that a new condition was
confronting them and that established
customs were being menaced. The
trouble was quickly traced to the auto
mobile and 1t was studied. 1t was soon
noted that the soft rubber tire was the
highway menace. 1t crushed no rock
itself and therefore contributed no
quota of the needful surface dust bind
err while the tremendous tractive force
Of the rear wheels drew up the dust
made by the iron tired wagons and
sent it whirling away over adjacent
lands.
Those who witnessed the expert
ments of Thursday neaT the national
capital could not doubt for moment
that the various road experts all over
the world are correct in the opinion
that rapidly driven automobiles ara
rapidly tearing up the surface of the
macadam road, for not only were huge
clouds of dust lifted into the air and
blown off the road, but careful exam
ination showed that the material under
the wheel tracks or the nlacnlne was
distinctly loosened and raveled even
during the short period Of these tests
No Effects Noticeable
No such effects were noticeable after
the passing of iron tired vehiclse; the
series of tests beginning with the pass
ing of a horse drawn vehicle. This
was photographed as il moved along
and also as the wagon tires passed a
given mark. Then the automobiles
were sent over the course. The first
was a heavy weight touring car NOV
ing at five miles an hour. A series of
pictures was made of that car on It's
many journeys at varying rates of
speed until it's maximum of forty-fve
miles an hour was attained. Then the
work was taken up by the huge racer
which tore down the road first at a
speed of fifty miles an hour, then at
fifty-five. sixty and finally at sixty
five. It fairly lifted the road surfacing
material as it sped along. regular ridges
Of rock dust rising in front OF the rear
wheels and floating away In binding
clouds Other tests were made and
other pictures taken of various tyres
Of heavy limousine cars and runa-
bouts. 1t was plainly noticeable and
4 hat he n