1. Saving by machine computation as
compared to plotting and planimetering
cross sections $240 per mi.
2. Saving by taking digital data
directly from stereo model to punch cards,
as compared to use of a contour map $ 55 per mi.
3. Saving by using adjusted photogram-
metric quantities for payment in lieu of
taking field cross sections of final line $420 per mi.
Other indications of the economy of the system come from
descriptions of its application to particular jobs. These in-
clude such glowing statements as:
1. The man-hours involved from initial location studies
through the production of plans are reduced by 60%.
2. The dollar savings in design effort for comparable
jobs are up to 40%.
3. By refining the alignment and grade through use of
the system, the actual excavation required was reduced by 6%.
4. The reduction in construction costs through more
economical alignment and grade are greater than the total cost
of engineering under the old methods.
Even allowing for the natural enthusiasm of the proponents
of the new system, it is quite apparent that substantial savings
in engineering effort, design cost, and construction cost can
be realized. One word of caution, however, should be inter-
posed. In urban areas, where construction costs are highest,
route location is rarely dictated by earthwork considerations.
Property acquisition costs, interchanges with existing routes,
underground structures, etc., are the controlling factors.
Under such conditions, the new system is not particularly
applicable.
THE FUTURE
The photogrammetric-electronic system of highway design,
as described herein, is fully operational. It has already
eliminated much of the sub-professional drudgery, leaving the
design engineer to concentrate his efforts on the decisions
requiring sound judgment. However, a careful examination of
the system shows that there are still several areas in which
relatively routine operations are being performed by human
labor, and hence are subject to the errors of human observation.
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