Eye-level height =
Vd = 2 x 1.75 m = 3.5 m
Hd = (75 paces + 125 paces) x 0.75 = 200 x 0.075 = 150 m
Percent of slope =
x 100 =
x 100 = 0.023 x 100 = +2.33% = ♂ 3%
Figure 1-4. Pace Method to Determine the Percent of Slope
Sharp curves along a specified route with a radius of 45 meters and less are
represented on maps or overlays by a triangle. The vertex (the point opposite to and
farthest from the base) of the triangle will point to the geographical location of the curve on
the overlay or map. In addition, the measured value (in meters) for the radius of curvature
is written outside the triangle. A series of sharp curves is represented by two triangles, one
drawn inside the other. The vertex of the outer triangle points to the geographical location
of the curve. The number of curves and the radius of curvature at the sharpest curve of the
series are written outside the triangle (Figure 1-5).
Figure 1-5. Curve Symbols
There are several methods that can be used to measure curves. These methods
are discussed below.
(1) The radius of curvature may be estimated by using a tape to swing an arc
(Figure 1-6, page 1-6). The curve is inscribed as part of a circle by swinging an arc with a
tape from an estimated center of a circle. The length of the tape from the center of the circle
to its circumference is the radius of curvature.