Vertical alignment design
After the
horizontal geometric design, vertical curve design can be conducted to ensure
continuous grade variation for safety and comfort. Stopping sight distance and curve length
will be calculated using the formula suggested in the AASHTO manual [1]. Further discussion on the equations used is
included in the Appendix. Click on the vertical alignment icon
tool
from the
toolbar to open the vertical alignment window as shown in Figure 9(a). The
previously entered elevation information of each station is plotted versus the
calculated road distance from the starting station based on the horizontal
design. Click on the elevation landmark on the graph
to view its location
and elevation information in status bar, Figure
9(b). Click on the line segment
to view the grade information in the status bar, Figure
9(c).

Figure 9(a) Elevation profile of
stations/landmarks

Figure 9(b) Station
information

Figure 9(c) Grade
information