Roads in the United States on Large- and Medium-Scale Maps

a. Road Classifications on Large-scale Maps.

Roads within the limits of the United States are classified on large-scale maps as--

b. Road Classifications on Medium-Scale Maps. The classifications on medium-scale maps are the same, except for hard-surface roads, where a distinction is made between roads two lanes wide and roads more than two lanes wide.

c. Hard-Surface, Heavy-Duty Roads. Roads of this classification carry heavy truck loads in all weather with a minimum of maintenance. The construction is usually of portland-cement concrete, bituminous concrete, or sheet asphalt, rock asphalt, bituminous penetration, or mixed bituminous on a heavy foundation. Brick or block roads are also included in this category.

d. Hard-Surface, Medium-Duty Roads. These roads carry medium-heavy truck loads in all weather. Occasional maintenance is required. Construction is usually a bituminous-penetration or mixed-bituminous surface, or bituminoustreated surface on a light foundation.

e. Improved, Light-Duty Roads. These roads carry light loads in all weather. Periodic maintenance is usually necessary. Construction consists of stabilized or oiled-surface gravel or stone, graded and drained gravel or stone, or graded and drained soil surface. Included in this category are hard-surface roads less than two lanes wide and improved private roads which normally are not practical for use in rerouting of traffic in emergencies.

f. Unimproved Dirt Roads. These roads are suitable only for light loads in dry weather. They are without surface improvement and are seldom maintained. Included are abandoned roads, fire roads, and lumber roads.

g. Trails. The map shows important foot paths, foot trails, and pack trails which can accommodate ¼-ton trucks in dry weather. Minor and short connecting trails usually are omitted.

h. Symbols. The following contain the approved symbols for roads in the United States.