Middlebury register. (Middlebury, Vt.) 1886-1937, 1898-12-30
PENNSYLVANIA ROADS.
How Highways Are Constructed In Ale
ghany County.


The highways of Allegheny county
are supervised by practical engineer
of wide experience, F. w. Patterson, and
the method of construction is described
in the Pittsburg Press.
The transforming of the bad roads of
this mountainous county into good ones
was begun in September, 1897, and as a
result l6 miles are completed and in use,
and about 20 miles are now in course of
construction. The traveller or casual OBJ
server passing over one of these new
roads has little idea of the amount of
material and labor required to produce
the hard, smooth surface and the easy
grade.
The method of construction adopted
for these roads is what is known as mac
adamizing, that system of building be-
ing best adapted to the highways of
this county. The surface of the road
does not indicate its substantial quail
ties, as it is much like any smooth road
would appear under favorable circum-
stances, except that it is carefully
crowned in the center and rounds so
nicely into the clay road on either side
that were it rot for the difference in the
color it would be difficult to tell Just
where the macade lied portion began.
This statement is applicable only when
the clay portion is at its best. neither
rough, muddy nor dusty. 1t is under
unfavOrable circumstances that the
macadamized road stands pre-eminent.
Continued wet weather does not affect
it in the least, and a long drought only
produces a thin blue dust on the surface
caused by the grinding of the lgonier
screenings under the wheels of passing
vehicles.
The standard construction adopted for
the Allegheny county roads is as fol-
lows: After the road has been graded,
sloped and guttered an excavation is
made In the center II feet wide and
sufficiently deep to bring the surface
wht completed Is inches above the
surface of the cutters, to provide a
crown, in order that the water may be
shed rapidly. The bottom OF this exca-
walton is then rolled with ten ton steam
roller. Eight inches of native stone,
broken to 81 inches in diameter, is filled
in and the roller again applied. If the
ground be low or soft, telford fOunda-
ton is substituted for the broken stones.
On this is a layer of ligonier stone,
crushed to 2i inches in diameter, which
is also rolled. Then comes another
layer of the same material, but of small
or size, II inches thick. which serves to
key the larger stone, The roller is again
brought into requisition.
The whole is finished with LAYER Of
fine ljgonier screenings, which fiji the
nterstices and form a smooth surface.
This is wet and rolled firm. When used
for time, it becomes so hard that it is
almost like concrete. The road engi-
neers adopted the foregoing as the
standard construction for all the country
roads improved, after a careful study of
the methods employed by road builders
both in this country and abroad. The
- miles of road now completed have
cost the country on an average $4,000
per mile, which, when the enormous
cuts and fills made necessary to reduce
the grade in many places are considered,
is not excessive. The cost of grading
alone has averaged nearly $4,000 a mile.
This. of course, varies according to the
physical and Typographical character of
the country through which the road
passes