The daily telegram. [volume] (Clarksburg, W. Va.) 1901-1926, 1912-06-24

3 ID.
An OILED MAcApAM ROAD WITH MACHINE
TRAVELLING SIXTY MILES PER RoUK--Hd
DUaT
chimes owned in the United States, and
the number Is increasing at a marvel:
ous rate. D
The fact that must give us concern
Is that the old methods Of construction
which have stood every test for more
than 100 years are inadequate to meet
the conditions Of this new form Of traf.
&c and that we are In the midst. OF a
transition period which must eventual.
~ reVoluhonize the science and art OF
the road builder, The highway en-.
gineer Of today is called upon to aseer
tain in what way the automobile in.
lures the !yoqd what Is the exact cause
Of the injury, and finally to devise an
adequate remedy. q.
When Tresaguet, the great French
engineer, made his report to the coun
Ell OF bridges and roads in lT715 he SET
forth the principles Of construction
which, as modified and ndded to BY
John L, Macadam in the curly purt Of
the nineteenth century. have proved
adequate until the twentieth century.
These great road builders and theft
successors sought to secure roud ca.
pable of withstanding the wear of iron
tired horse drawn vehicles. for the mo
tor driven vehicles had no place in
their philosophy. They worked upon
the theory that the dust nbraded from
the crushed stone would ill the yoids
between tile angular fragments aud
when wet serve us a cement. thereby
making the road surface practically q
monolith. The iron shod horses and
the iron tired wheels passing over the
roud from time to time were depended
upon to wear OF u sufficient amount Of
rock dust to replace that carried away
by wind and water, and this under the
action Of moisture recemented, thereby
automatically renewing the bond of the
road surface.
The rubber tired wheels, moving at
excessive speed, fail to produce any
new dust from the rock. but the ire
rnendous shearing effect of the driving
wheels 'ioosens this dust, and us the
body of the machine displaces large
volume of mir the detected currents
carry the rock dust OF the road, there.
by erecting permanent loss Of the all
essential binder. 1t follows that the
road is soon stripped OF Its fne bind.
ing material, exposing the upper or
wearing course OF the. stone These
stones robbed Of the binding material
are soon loOsened by the shear OF the
driving wheels, leaving the road badly
raVeled or dlsintegrated 1t is. Of
course. apparent that the effects de.
ScEbed are greatly intensified on
curves, where skiddlnS is most fire
quent.
Highway and mechanical engineers
have given much study to the notion Of
the automobile on the road surface.
and many Ingenious theories have been
advanced While it Is true that the
slipping OF tile tire, skidding. shape OF
the car Body, suction Of the pneumatic
tires. all contribute to produce the eff.
feet, tile most conclusive experiments
seem to wArrant the assertion that the
great trurttve force or shear exerted
by the driving wheels Of motorcars is
the main factor Ufinjury.
A series Of tests conducted by the
United States office Of public roads in
1908 produced some interesting results
along this line. Cars OF various weights
and types were run over a measured
course ut different rates OF speed aud
right angle photographs taken of each
run. A sixty horsepower car stripped
for racing. weighing with its driver
and mechanician about $500 pounds
was driven over this stretch Of road at
rites of speed varying from five to six
ty miles per hour. the speed being In.
sreased 6Ve miles yer hour for each
trip over the road. Up TO fifteen miles
an hour little or no effect was produced
On the road. but from twenty miles an
hour the effect WIS striking with each
Increase in speed. These demonstra-
donS proved that little or no effect Is