1. The sheriff may, in an emergency or when he deems it essential for the performance of the official duties of his office, permit the use of personally owned motor vehicles by members of his department, but only when no county-owned vehicles are available. When such use is authorized, members of the department using their own motor vehicles shall be reimbursed out of the county treasury for each mile actually and necessarily traveled in the performance of their official duties as prescribed by subsection 2 of this section at a rate equal to the rate prescribed by the Internal Revenue Service for allowable expenses for motor vehicle use expressed as an amount per mile.

2. When mileage is allowed, it shall be computed from the place where court is usually held in the county, and when court is usually held at more than one place, such mileage shall be computed from the place from which the sheriff or deputy sheriff travels in performing the service. When two or more persons who are summoned, subpoenaed, or served with any process, writ, or notice, in the same action, live in the same general direction, mileage shall be allowed only for summoning, subpoenaing or serving of the most remote. At the end of each month, the sheriff and each deputy who has such a mileage claim shall file with the county commission an accurate and itemized statement, in writing, showing in detail the miles traveled by such officer, the date of each trip, the nature of business engaged in during each trip, and the places to and from which he has traveled. Such statement shall be signed by the officer making claim for reimbursement, verified by his affidavit, and filed by him with the county commission. Whenever claim for reimbursement is made by a deputy, his statement shall also be approved in writing by the sheriff, who shall also file an affidavit that all such miles traveled were necessary or essential to carry out the duties of his office, and that no county vehicles were available. The county commission shall examine every claim filed for reimbursement, and if found correct, the county shall pay to the officer entitled thereto, the amount found due as mileage.

3. Reimbursement for mileage allowed as a result of duties performed in connection with a civil action may be paid in the manner prescribed in subsection 2 of this section regardless of the status of the civil action for or in which the mileage was incurred.

4. When any sheriff is to be reimbursed by the state for mileage allowed for delivery of a prisoner to the department of corrections, the county commission may advance payment to the sheriff for such delivery along with other mileage allowances, and the reimbursement from the state shall be paid to the county commission by the sheriff as soon as it is received.