54 U.S.C. § 101511 — Authority of Secretary

(a) Roads and Trails in System^* Units. The Secretary^* may build, rebuild, and improve roads and trails — including bridges — inside System units.

(b) Approach Roads. (1) Designation. When it's in the public interest, the Secretary may designate certain roads as "System unit^* approach roads." To qualify, a road's main purpose must be carrying travel to the System unit; it must cross land that is at least 90 percent federally owned; and it must connect the unit's highways to a convenient point on, or leading to, the National Highway System. (B) Length limits. A designated approach road generally cannot be longer than 60 miles, measured from a System unit gateway to the nearest convenient National Highway System road — or 30 miles if the approach road is itself on the National Highway System. No more than 40 miles of any single approach road can be designated within any one county. (C) A designated approach road becomes a supplementary part of the System unit's own highway system.

(2) Construction, reconstruction, and improvement. (A) The Secretary may build, rebuild, and improve these designated approach roads, including bridges, and may either arrange for State or county authorities to maintain them or maintain them directly when necessary. (B) No more than $1,500,000 total may be spent each year on constructing, rebuilding, and improving all System unit approach roads combined.

(3) Approval of Secretary of Agriculture required. If an approach road is proposed to run across or within a national forest, the Secretary must get the Secretary of Agriculture's approval before construction starts.

(c) Agreement With Secretary of Transportation. Under an agreement with the Secretary, the Secretary of Transportation may carry out any provision of this section.