Ala. Code § 40-17-370 — Levy, Administration, and Collection of Additional Excise Tax

(a) Effective for tax periods beginning after August 31, 2019, an additional excise tax of six cents ($0.06) is imposed on each net gallon of gasoline and diesel fuel.
(b) Effective October 1, 2020, this additional excise tax is increased by two cents ($.02) to eight cents ($0.08) on each net gallon of gasoline and diesel fuel.
(c) Effective October 1, 2021, this additional excise tax is increased by two cents ($.02) to ten cents ($0.10) on each net gallon of gasoline and diesel fuel.
(d) Beginning October 1, 2023, and on July 1 of every other year thereafter, the excise tax rate provided in this section shall be adjusted by the percentage change in the yearly average of the National Highway Construction Cost Index (NHCCI) issued by the U. S. Federal Highway Administration (FHWA) for the most recent 12-month period ending December 31, compared to the base year average, which is the average for the 12-month period ending December 31, 2020 and rounded to the nearest whole cent. The maximum amount of increase or decrease in the excise tax rate shall not exceed $.01 per net gallon of gasoline or diesel fuel and shall take effect every other year. The Department of Revenue shall notify each terminal supplier, position holder, licensed distributor, and importer of the tax rate adjustment applicable under this subsection on or before March 1.
(e) This additional excise tax shall be levied, administered, and collected in accordance with Article 12, provided that the due date for payment and filing of returns for all motor fuel taxes, including the additional amounts levied in this article, shall be the 20th day of the month following the month in which the tax accrues, except as otherwise provided in Section 40-17-340 (d), and the bond required under Section 40-17-335 (a)(1) shall not exceed three million dollars ($3,000,000). The net tax proceeds, after the cost of collection and distribution to the Alabama Highway Finance Corporation authorized by this article shall be distributed to the state and to each county and municipality for transportation infrastructure purposes in accordance with this article.