Any witness attending any such hearing or investigation shall immediately upon his or her discharge as a witness be paid by the party requesting the subpoena an amount not to exceed the per diem expense allowed to Alabama state employees for in-state travel and the actual cost of his or her transportation to and from the place of the hearing; not to exceed the mileage rate allowed to Alabama state employees for in-state travel.
Ala. Code § 34-24-364 (1975)