Evening star. [volume] (Washington, D.C.) 1854-1972, 1945-02-11

the facility in Virginia and the District total capacity OF
four lanes in each direction is necessary.
Bridge capacity is primarily question of traffic
engineering AS far as known the Planning Commission
has never expressed the opinion that future traffic de-
mands will not require the eight lanes OF capacity 1t
itself with the statement that should future
traffic exceed the sxlane capacity proposed by
it, another bridge should be built at Alexandria Regard
less of the merits of such bridge, the Commissioners
agree with the statement of the administrator of public
roads that it considered Judgment that 1t would
be unwise to construct facility of inadequate capacity
with the hope that such act would cause the building
of an additional facility at another location and that
the two combined would solve the problem"
Expects Heavy Traffic Increase.
On the other hand, the Commissioners have been
impressed by traffic engineering study presented by T.
H. Macdonald administrator of public roads, after con-
sultaton with several OF extensive experience IN
problems in the design and construction OF modern
highways parkways and bridges This analysis leads
to the conclusion that the facility should be designed for
peak load of 5000 vehicles in each direction for
period of of hour, and that about ID
per cent vehicles should be assumed to be trucks
(The) 194l average daily traffic A5oO vehicles, OF
which is per cent trucks The 1860 probaby not
years after competion) average daily trac
Is estimated to $4,000 vehicles (no allowing for any
DETECTION Of peak hour traffic from Memorial Bridge
Practical peak hour capacity OF Memorial Bridge was
"A normal distribution of the expected average daily
traffic 1860 would result in numerous one-way peak
loads well in of 5000 vehicles per hour but the
observed distribution at Highway Bridge Is such that II
would be safe to design for that figure. During such
periods peak traffic disruption of the smooth flow
such as vehicles slowing down to make loop turns or
vehicle stopped for any not only backs up trac
but has been known to stop traffic completely.
eff facility at Fourteenth street is constructed for
only three each direction and the left turning
traffic. contributing in of one-fourth OF the total
is required negotiate the inner loop of cloverleaf
it is probable that future traffic will meet congestion
very compelling for constructing at this location
design of complete adequacy and attractveness 10
traffic" 1t might be added that when the decision to
build bridge the Anacostia River at Penn
syvania made the existing traffic was less
than third of that now existing on Highway Bridge,
and was not complicated by heavy truck trafnc and
exceedingly heavy turning movements. Experience has
shown that this decision was correct
Two Four-lane Bridges Best.
The provision fourane capacity in each direction
can adequately provided by two bridges OF four
lanes each and such facility will not detract from the
Jefferson Memorial
When the two-bridge scheme first proposed by the
Public Administration, the principal objection OF
the Planning Commission directed, not to the fact
it would provide capacity direct too much
traffic to the midcity but that the two bridges
would have aesthetic effect the Jefferson
Memorial It employed F. L. Olmsead, expert landscape
architect study this phase of the subject Mr. Omstead
submitted lengthy report which was referred to the
Fine Arts Commission generally recognized as an authority
such matters It would that the atters action in
approving the twobrdge scheme effectively and authori-
tatively disposed of the question
AS expressed by the chairman II do not subscribe to the
(of Mr. osted concerning the very regrettable
impression that would be created by having three bridges
rather than this section of the Potomac River
That statement very naturally debatable since It is based
upon aesthetics and in that of thought there be
many there reasons to debate it." In
this opinion, the Commissioners concur.
g. single sx-lane bridge will not meet prospective
/rahc needs and any in present construction
costs will be more than balanced by the cost of another
necessary crossing in the future
1t Is conceded that the twobridge scheme will cost is
to 20 cent more than the single brdge-based upon
detailed study OF this site by competent engineering
firm, and not general estimate by result
Of which tn Park and Planning Commission has announced
this excess cost as IS cenand it is equally that
single four-lane bridge similar to the now in exist
tsee TWolBRIDoEs, Page c-0J
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