Table 2-1. Criteria for the Determination of Limiting Characteristics
Limiting
Criteria
Symbol
Characteristics
Curves with a radius of curvature of 25 meters and less. Sharp curves are
Sharp curves
c
also reported as obstructions.
Gradients with a percent of slope of 7 percent or steeper. Steep gradients
Steep gradients
g
are also reported as obstructions.
Ditches, crown or camber, or culverts that are inadequate; ditches and
Poor drainage
d
culverts blocked or otherwise in poor condition.
Weak foundation
Foundation material that is unstable, loose, or easily displaced.
f
Surfaces that are bumpy, rutted, or potholed to an extent likely to reduce
Rough surface
s
convoy speeds.
Excessive camber
Crown or camber that is falling away so sharply as to cause heavy vehicles
j
or super elevation
to skid or drag toward the shoulders.
c.
The road surface material is the next symbol found in the road classification
formula. The letter symbols that are used to represent road surface materials are shown in
Table 2-2.
Table 2-2. Symbols for Road Surface Materials
Symbol
Material
Route Type
k
Concrete
Type X; generally heavy duty
kb
Bituminous (asphaltic) concrete (bituminous plant mix)
Type X; generally heavy duty
p
Paving brick or stone
Type X or Y; generally heavy duty
pb
Bituminous surface on paving brick or stone
Type X or Y; generally heavy duty
Bitumen penetrated macadam, water-bound macadam
rb
Type X or Y; generally medium duty
with superficial asphalt or tar cover
Water-bound macadam, crushed rock or coral, or
r
Type Y; generally light duty
stabilized gravel
l
Gravel or lightly metalled surface
Type Y; generally light duty
Bituminous surface treatment on natural earth, stabilized
nb
Type Y or Z; generally light duty
soil, sand clay, or other select material
b
Undetermined types of bituminous material
Type Y or Z; generally light duty
Natural earth stabilized soil, sand clay, shell, cinders,
n
Type Z; generally light duty
disintegrated granite, or other select material
Classify X, Y, or Z depending on the
v
Various other types of material not mentioned above
type of material used (indicate the
distance along the route)
d.
The length of the road is represented next in the sequence and is expressed in
kilometers. The length of the specific section of road may be shown in brackets at the end of
the formula. This is not required and is optional for the reconnaissance team leader.
2-5
EN 5622
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