Each member of the board shall receive the expense allowance as provided by subsection (b) of Code Section 45-7-21 and the same mileage allowance for the use of a personal car as that received by other state officials and employees or a travel allowance of actual transportation cost if traveling by public carrier within this state. Each board member shall also be reimbursed for any conference or meeting registration fee incurred in the performance of his or her duties as a board member. For each day's service outside of the state as a board member, such member shall receive actual expenses as an expense allowance as well as the mileage allowance for the use of a personal car equal to that received by other state officials and employees or a travel allowance of actual transportation cost if traveling by public carrier or by rental motor vehicle. Expense vouchers submitted by board members are subject to approval of the president and executive director. Out-of-state travel by board members must be approved by the board president and the executive director.