1.75 m

1.75 m

125 paces

m

1.75 m

75 paces

Given:

Eye-level height =

1.75 m

Pace

=

0.75 m

Vd = 2 x 1.75 m = 3.5 m

Hd = (75 paces + 125 paces) x 0.75 = 200 x 0.075 = 150 m

Vd

3.5

Percent of slope =

x 100 =

x 100 = 0.023 x 100 = +2.33% = ♂ 3%

Hd

150

Figure 1-4. Pace Method to Determine the Percent of Slope

b.

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).

3/25

22

Figure 1-5. Curve Symbols

c.

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.