able to make a more careful study of some certain sections of
road and this may be done by waking over the section in question in
order to make a more deliberate survey of the features to be
considered than is possible when riding in a motor car.

Factors other than relative lengths of routes will obviously determine
the cost of improvement and the comparative merits of the improved
roads. Some special characteristic of a road, such as bad railroad
crossings or a few bad hills, may eliminate a route, or availability
of materials along a route may offset disadvantages of alignment or
grade.

In special cases, complete surveys of routes may be required finally
to select the best route, but these instances are few in number.

=Road Surveys.=--When a road has been definitely selected for
improvement, a careful survey is made to furnish information for the
preparation of the plans. This will consist of a transit survey and a
level survey.

The transit survey is made by running a line between established
corners following the recorded route of the road, or if no records are
available or the road is irregular in alignment, by establishing
arbitrary reference points and running a line along the center line of
the existing road or parallel thereto. The topography is referenced to
this line in such completeness that it can be reproduced on the plans.
The level survey consists in taking levels on cross sections of the
road at one hundred foot intervals, and oftener if there are abrupt
changes in grade. Special level determinations are made at streams,
railroad crossings, intersecting roads or lanes and wherever it
appears some special features of the terrain should be recorded.

From the surveys and such other information as has been assembled
relative to the project, a plan is prepared which embodies a design
presumed to provide for an improvement in accordance with the best
highway practice.

THE PROBLEM OF DESIGN

It will be convenient to consider separately the components of a road
design, although in the actual design the consideration of these
cannot be separated because all parts of the plan must fit together.

=Alignment.=--The alignment of the road is determined to a
considerable extent by the existing right-of-way, which may follow
section lines, regardless of topography, as is the case with many
roads in the prairie states, or it may follow the valleys, ridges, or
other favorable location in hilly country. I