Ala. Code § 37-2-11
Whenever any transportation company shall refuse or neglect to establish a joint rate or rates for the transportation of persons or property, the commission may, upon notice to such transportation company or companies, and after an opportunity to be heard, as provided in this title, fix and establish such joint rate or rates, and if the transportation companies, parties thereto, shall fail to agree upon apportionment thereof within 20 days after the service of such orders, the commission may, upon like hearing, issue a supplemental order declaring the apportionment of such joint rate or rates, and the same shall take effect of its own force as part of the original order. In cases relating to the fixing, regulating or prescribing of joint rates of two or more transportation companies, such transportation companies may be joined in one proceeding before the commission.
Ala. Code § 37-2-11 (1975)