The Brownsville daily herald. [volume] (Brownsville, Tex.) 1897-1910, 1908-05-14
MOTORS AT A
MILE A MINUTE
Federal Tests of Effect Of Spread.
ing Automobiles.
On Famous Conduit Road Fast Machines
Test Theory that Rubber Tired
Vehicles at High Speed Ruin
Macadam Roads.

/ w kOh, IL 3t1ay 100
A two ton racing automobile NOV
ing at something in excess of {
minute, while an impenetrablt
CLOUD of fog-grey rock dust hung
to the horizon and marked the
speeding course of the big machine
was the sight witnessed recently
by travellers on the famous conduit,
road a dozen miles from Washing
ton.
The seemingly pronounced viola
ton of the speed ordinances was
countenanced by two of the Ma
tons federal OBSERVATION-DISCLOSURES
culture and War-however, the
rushing motor-car having been
pressed into requisitiou by L. w.
Page, director of the Office of Pub
lie Roads, and DIR. Allerton S.
Cushman. assistant director. in the
effort to determine the effects of
automobile traffic upon macadam
highways, and the stretch of thor
oughfare was placed at their dis
posal 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 5 to SIS miles
an hour. corps of skilled photo
graphers, equipped with the most
modern devices for photographing
vehicles at very high speeds. made
accurate records of the various
tests.
1t has long been known to high
way engineers that automobiles
were rapidly 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 cause
of the damage done. To under
stand how the soft broad tires of
the modern motor car can work an
injury to a surface that not only |
withstands, 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
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
Gil in all the interstices between
he stones but would also form a
surface dust binder; the WRITINGS
md rollings tending to cement the
lust into a shell-like surface and
hus make the entire road one traf-
c-withstandiug, understanding
mass.
They reasoned well and wisely.
The macadam roads lived up to
he theories of their inventors and I
with the passing years {
Until the advent of the automobile.
/ was but short time after it
anne into vogue that highway en-
.iDeers in all civilized lands learn
d that a new condition was
them and that estab-
ished customs were being
nenaced. The trouble was
uickly traced to the automobile :
nd it was studied. It was soon
oted that the soft rubber tire was |
be highway menace. 1t crushed +
% rock itself and therefore con-
ributed no quota of the needful :
urface dust binder, while the ire r
,endous tractive force of the rear 6
'heels drew up the dust made by :
he iron-tired wagons and sent it i
away over adjacent a
lnds. r
Those who witnessed the ex- {
eriments near the National Capt. {
II could not doubt for moment !;
nat the various road experts all =
yer the world are correct in the {
pinion that very rapidly driven r
are rapidly tearing up +
ne surface of the macadam road, u
,r not only were huge clouds of q
ust lifted into the air and blown 6
# the road. but careful examina- r
on showed that the material I'M
er the wheel tracks of the machine
'as distinctly loosened and ravelled
ven ,d1ting the short period of t;
lese tests. Iii
No such effects were noticeable n
fter the passing of iron tired D
the series of tests begin
ing with the passing of horse
rawn vehicle. This was photo
raphed as it moved along and also B
al 0nmnonu