TM 5-822-2/AFM 88-7, Chap. 5
Figure
3-3. Method of layout of widening and superelevation of spiral lanes
vehicles required to furnish services are capable of
projects for two-way, two-lane highways will be furnished
operating on a continuous 15 percent grade, it would not
to Headquarters, Department of the Army, (DAEN-ECE-
be economical to provide a road with restricted length of
G) Washington, DC 20314-1000.
(b) Curves. Generally, vertical curves
10 or 12 percent grade as required in table 1-1. In this
instance the maximum grade should be 15 percent.
should be provided at all points on roads or streets
Selection of minimum grade for use in design of roads
where there is a change in longitudinal grade. The major
and streets is dependent primarily on drainage
control for safe vehicle operation on vertical curves is
requirements. Minimum grades are shown in tables 1-1
sight distance, and the sight distance should be as long
and 1-2. Designs for two-way, two-lane highways with
as possible
climbing lanes are discussed in AASHTO publications.
Justification for inclusion of climbing lanes in Army
3-16
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