Evening star., 1944-07-21
Bridges
Continued From First Page.)

avenues will not be in excess of the
capacity of those intersections and
will not tend to increase congestion
in the midcity area. Any proposed
diversion of traffic from this area
will depreciate property values
therein"
The city heads stated that the
planning group has never expressed
the opinion that future traffic de-
mandS will not require the eight
lanes of capacity. In fact, the early
studies by its staff were based on
single eight-lane bridge. No expert
traffic engineer has been employed
to study this phase Of the problem,
and so far as known, no member of
the commission nor it's staff claims
to be an expert on the subject"
Cost Will Be Greater.
1T is true" the statement con-
tinued, that the two-bridge scheme
will cost Is to 20 per cent more than
the single bridge-an estimate based
upon detailed study of this site by a
competent engineering firm and not
upon general estimate by some one
as result of which the Park and
Planning Commission has announced
this excess cost as IS per cent ."
Answering an objection of the
NCPPC that two bridges would throw
too great volume of traffic in the
downtown section of Washington,
the Commissioners said Mr.. McDon-
AIDS study showed that the north
approach of the Maine avenue grade
separation can accommodate three
lanes in each direction and the
streets on the north can be made to
distribute this traffic easily"
Traffic studies made in June and
this month between and $50 m
indicate that 20 per cent of the
traffic entering the District by High
way Bridge turns off at Maine ave-
nue. S.W., II per cent at D street
S.W., and 10 per cent at Inde-
pendence avenue S.W., the Com
missioners reported. Only At per-
cent, they added, moves on Four
teenth street north of Adams drive
NV.
Six Submit Designs.
This northbound traffic on Four
teenth street has a street capacity
OF three lanes when it reaches Con-
stitution avenue, and assuming that
all four lanes over the bridge are
used to full capacity, it is difficult
to see how At per cent of this, or
less than two lanes, will congest a
street with three-lane capacity"
they concluded.
The plans approved today were
by Howard, Needles, Tammen g.
Bergendoff, engineers of New York
City and Kansas City, Mo-, who were
awarded contract for the prepara-
ton of working drawings. Henry
R. Shipley, Boston architect, will be
architectural consultant with the
firm. Six engineering firms sub
mitted designs.
The new crossing will consist of
two identical bridges, about 400 feet
apart and each with four-lane
traffic capacity. There will be Is
steel deck girder spans, each ap-
proximately 100 feet in length, rest
ing on stone faced piers. Naviga-
tion features will have to be passed
upon by the War Department, but
openings for river traffic are planned
for each structure.
Quote Mcdonald.
In justifying the eight lanes, the
Commissioners quoted Mr.. McDon-
aid as follows:
AN analysis leads to the conclu-
sion that the facility should be
designed for a peak load of 5000
vehicles in each direction for a.
period Of time in excess of an hour
: The 1860 (probably not more
than 10 years after completion)
average daily traffic is estimated
to be $4,000 vehicles. A normal
distribution of the expected average