Except as otherwise specifically provided, authorizations from the Highway Trust Fund (other than the Mass Transit Account) to carry out this title shall be available for obligation on the date of their apportionment or allocation or on October 1 of the fiscal year for which they are authorized, whichever occurs first.

Except as otherwise specifically provided, funds apportioned or allocated pursuant to this title in a State shall remain available for obligation in that State for a period of 3 years after the last day of the fiscal year for which the funds are authorized. Any amounts so apportioned or allocated that remain unobligated at the end of that period shall lapse.

Any funds released by the final payment for a project, or by modifying the project agreement for a project, shall be—

(1) In general.— Funds apportioned or allocated to a State for a purpose for any fiscal year shall be considered to be obligated if a sum equal to the total of the funds apportioned or allocated to the State for that purpose for that fiscal year and previous fiscal years is obligated.

Any funds released by the final payment for a project, or by modifying the project agreement for a project, shall be—

(A) credited to the same class of funds previously apportioned or allocated to the State for the project; and

(B) immediately available for obligation.

(3) Net obligations.— Notwithstanding any other provision of law (including a regulation), obligations recorded against funds made available under this subsection shall be recorded and reported as net obligations.

Funds made available to the State of Alaska and the Commonwealth of Puerto Rico under this title may be expended for construction of access and development roads that will serve resource development, recreational, residential, commercial, industrial, or other like purposes.

(Pub. L. 85–767, Aug. 27, 1958, 72 Stat. 897; Pub. L. 89–574, § 7(a), Sept. 13, 1966, 80 Stat. 768; Pub. L. 94–280, title I, § 117(a), May 5, 1976, 90 Stat. 436; Pub. L. 95–599, title I, § 115(a), Nov. 6, 1978, 92 Stat. 2697; Pub. L. 96–106, § 5(a), Nov. 9, 1979, 93 Stat. 797; Pub. L. 97–424, title I, § 115, Jan. 6, 1983, 96 Stat. 2107; Pub. L. 100–17, title I, §§ 114(a)–(c), (e)(2)–(4), 115, Apr. 2, 1987, 101 Stat. 150–153; Pub. L. 102–240, title I, § 1020, Dec. 18, 1991, 105 Stat. 1948; Pub. L. 102–388, title IV, § 409, Oct. 6, 1992, 106 Stat. 1565; Pub. L. 105–178, title I, §§ 1106(c)(1)(B), 1107(b), 1226(b), June 9, 1998, 112 Stat. 136, 137; Pub. L. 105–206, title IX, § 9003(a), July 22, 1998, 112 Stat. 837; Pub. L. 109–59, title I, §§ 1111(a), 1501(b), Aug. 10, 2005, 119 Stat. 1171, 1235; Pub. L. 112–141, div. A, title I, § 1519(b)(1)(B), (c)(4), formerly (c)(5), July 6, 2012, 126 Stat. 575, renumbered § 1519(c)(4), Pub. L. 114–94, div. A, title I, § 1446(d)(5)(B), Dec. 4, 2015, 129 Stat. 1438.)