Evening star. [volume] (Washington, D.C.) 1854-1972, 1927-08-14
NEW j. S. HIGHWAY
PLANS EFFECTIVE
Roads Are Now Constructed
in Conformity With
Traffic Needs.

That a new conception Of the rela-
tionship between highways and motor
vehicles has come about, due to the
great expansion of the motor car, is
pointed out by Prof: Thomas X. Agg
of Iowa State College, in the August
issue of the Journal of the Society OF
Automotive Engineers. For long
time, according to the writer, highway
officials insisted that the motor vehicle
adapt itself to the highway. rather
than the latter adapting itself to the
motor vehicle.
This insistence now has given way
and every well-organized highway de-
partment Is attempting to adapt the
highways and roads to the traffic
passing over them. Construction and
maintenance programs are based upon
the fundamental principle of accom-
modating the present and future users
Of the highways, the writer states.
New Highway Conception.
"This new conception of the func-
ton of our highway systems, ne
asserts 'has made it imperative that
highway engineers obtain clear
understanding Of the interrelatlon OF
the highway and the vehicle that uses
it. of what the vehicle does to the road
Some of the things the vehicle does
to the road, according to Prof. Agg,
are: The tires wear away the road
surface, the wheel loads distort the
road surface, and the wheels subject
it to impacts of varying magnitude.
Some of the things the road sur
face does to the vehicle are: 1t Of
fers a resistance to the movement Of
the vehicle, wears away the tire tread
rubber, imparts reaction impacts to
the vehicle, the highway grade may
affect the time of travel and the fuel
consumption, slipperiness frequently
contributes to accidents, and dust and
mud cause deterioration of the We
hicle.
"These interrelations between the
vehicle and the road continues Prof.
Agg, "are the factors that afford a
starting point in the design or a nigh
way. but the design that is dictated
nv the theoretical considerations in
yolyed must often be modified to meet
such practical considerations as avail
able funds, topography, cost of right
of-way. and especially the letha:gy Of
nrblic officials toward that which is
new or abstruse.
1.-THE cost of any type Of road is
really the aggregate of the eXpendl-
ture required to build that type or
surface and keep it in a condition of
| maximum serviceability over an in
definite term of years. perpetually II
so desired. This cost includes original
cost and interest thereon, malnte-
nance and interest thereon and depre'
citation, each of which factors must
| include a proper part OF the cost or
| operation of the highway system, or
| overhead
Lower Type Cheaper.
'Tt seems that in general the lower
TYNE roads are actually cheaper than
| the higher types for any trafflc den
sity under which the road could be
| maintained in good condition. The
| justification for road Improvement
| must, therefore, be on some basis
other than that of conserving road
| funds.
ct is believed to be possible to show
that under certain conditions road I'M
provement saves in transportation
any road project produces wealth In
excess of It's cost. the necessary eX.
| penditure, no matter how great. is
good business The wealth produced
by road Improvement may be direct,
| in the form of lowered transportation
costs, or indirect as the result OF I'M
proved social and educational condi.
| tons.
possibilities for lowering the cost
Of highway transportation are Of two
kinds. One is by road improvement,
whereby the cost of vehicle operation
| is reduced to the economic minimum,
in so far as those costs are Influenced
by the highway. This is the task of
the highway engineer. The other Is
| by improvements in the vehicle.
whereby it's life is heightened and the
operating costs are as low as posi-.
BILE. Hence the future trend of high
way transportation depends largely
upon these two great bodies of techni
cal experts