(a) Carry-forward balances. Except as provided in paragraph (b) of this section, grant funds that remain unexpended at the end of a fiscal year and the expiration of an HSP shall be credited to the State's highway safety account for the new fiscal year, and made immediately available for use by the State, provided the State's new HSP has been approved by the Regional Administrator pursuant to §1300.14 of this part, including any amendments to the HSP pursuant to §1300.32.

(b) Deobligation of funds.

(1) Except as provided in paragraph (b)(2) of this section, unexpended grant funds shall not be available for expenditure beyond the period of three years after the last day of the fiscal year of apportionment or allocation.

(2) NHTSA shall notify States of any such unexpended grant funds no later than 180 days prior to the end of the period of availability specified in paragraph (b)(1) of this section and inform States of the deadline for commitment. States may commit such unexpended grant funds to a specific project by the specified deadline, and shall provide documentary evidence of that commitment, including a copy of an executed project agreement, to the Regional Administrator.

(3) Grant funds committed to a specific project in accordance with paragraph (b)(2) of this section shall remain committed to that project and must be expended by the end of the succeeding fiscal year. The final voucher for that project shall be submitted within 90 days after the end of that fiscal year.

(4) NHTSA shall deobligate unexpended balances at the end of the time period in paragraph (b)(1) or (3) of this section, whichever is applicable, and the funds shall lapse.