Ala. Code § 11-11-3
The county commission of each such county, in addition to all other powers which it may now have, is hereby empowered from time to time to authorize, sell and issue interest-bearing warrants of the county in anticipation of and payable solely out of that portion of the highway gasoline tax required by law to be distributed to that county. The said warrants may be in such denomination or denominations, may have such maturity or maturities not exceeding 20 years from their date, may bear interest at such rate or rates and payable at such times, may be made payable at such place or places whether within or without this state and may be sold at such time or times and in such manner, whether publicly or privately, all as the county commission of the county shall determine most advisable by resolution duly adopted at any lawful meeting of such county commission; provided, that the maturities of the said warrants shall be so arranged that the principal of and interest on the said warrants payable during any subsequent fiscal year of the county, when added to the principal and interest payable during each such subsequent fiscal year on all outstanding warrants of that county then outstanding, shall not exceed 50 percent of the amount of the highway gasoline tax that was distributed to that county during its fiscal year next preceding the fiscal year in which shall be issued the warrants authorized by this section to be issued; provided further, that if an irrevocable trust fund consisting of (1) cash, (2) direct general obligations of the United States of America, (3) bank certificates of deposit secured by not less than an equal face amount of direct general obligations of the said United States or (4) any combination of the foregoing items referred to in this proviso shall be established for retirement of all or any part of the principal of and interest on any outstanding warrants of that county, then to such extent as the retirement thereof shall be provided for by the said trust fund (including the cash therein and all sums due to be paid into the trust fund under the terms of any such United States obligations or of any such certificates of deposit), the said principal and interest shall for the purposes of this sentence be excluded from any computation of the amount of principal and interest maturing with respect to outstanding warrants. The general faith and credit of the county shall not be pledged to the payment of any warrants issued under this chapter, nor shall they be general obligations of the county, and for payment of the principal thereof and interest thereon the holder or holders thereof shall look solely to the county's share of the highway gasoline tax.
Ala. Code § 11-11-3 (1975)