2-18-503. Mileage -- allowance. (1) Members of the legislature, state officers and employees, jurors, witnesses, county agents, and all other persons who may be entitled to mileage paid from public funds when using their own motor vehicles in the performance of official duties are entitled to collect mileage for the distance actually traveled by motor vehicle and no more unless otherwise specifically provided by law.

(2) (a) When a state officer or employee is authorized to travel by motor vehicle and chooses to use a privately owned motor vehicle even though a government-owned or government-leased motor vehicle is available, the officer or employee may be reimbursed only at the rate of 48.15% of the mileage rate allowed by the United States internal revenue service for the current year.

(b) When a privately owned motor vehicle is used because a government-owned or government-leased motor vehicle is not available or because the use is in the best interest of the governmental entity and a notice of unavailability of a government-owned or government-leased motor vehicle or a specific exemption is attached to the travel claim, then a rate equal to the mileage allotment allowed by the United States internal revenue service for the current year must be paid for the first 1,000 miles and 3 cents less per mile for all additional miles traveled within a given calendar month.

(3) Members of the legislature, jurors, witnesses, county agents, and all other persons, except a state officer or employee, who may be entitled to mileage paid from public funds when using their own motor vehicles in the performance of official duties are entitled to collect mileage at a rate equal to the mileage allotment allowed by the United States internal revenue service for the current year.

(4) Members of the legislature, state officers and employees, jurors, witnesses, county agents, and all other persons who may be entitled to mileage paid from public funds when using their own airplanes in the performance of official duties are entitled to collect mileage for the nautical air miles actually traveled at a rate of twice the mileage allotment for motor vehicle travel and no more unless specifically provided by law.

(5) This section does not alter 5-2-301.

(6) The department of administration shall prescribe policies necessary for the effective administration of this section for state government. The Montana Administrative Procedure Act, Title 2, chapter 4, does not apply to policies prescribed to administer this part.