23 U.S.C. § 156 — Proceeds from the sale or lease of real property

(a) Minimum charge. Subject to section 142(f), a state must charge at least fair market value when it sells, leases, renews a lease, or otherwise lets someone use real property bought with federal highway money from the Highway Trust Fund (other than the Mass Transit Account). This rule does not apply to utility use and occupancy, or to a transportation project that qualifies for funding under this title. (b) Exceptions. The Secretary can excuse a state from the fair-market-value requirement for a social, environmental, or economic reason. (c) Use of federal share of income. The state must spend the federal government's share of the net income it earns under subsection (a) on projects that qualify for funding under this title.