7.3.3 Layout the Vertical Alignment
Since the speeds of aircraft on taxiways are considerably less than on runways; the criteria
governing grades, vertical curve length, and minimum distance between vertical curves are
not as stringent as for runways. The principal geometric design features of vertical
alignment are listed in Table 7- 11.
The FAA does not specify the line of sight requirements for taxiways, however, it is
recommended that from any point on the taxiway centerline the difference in elevation
between that point and the corresponding point on the parallel runway, taxiway, or apron
edge is 1.5% of the shortest distance between the points.
Table 7 - 11 Taxiway Gradient Standards, in ft*
*Source: Horonjeff, Mckelvey, Sproule, Young, 2010. " Planning and
Design of Airports".