(1) Section 20-10-147, MCA, allows school districts to budget each year in a bus depreciation reserve fund an amount that does not exceed 20% of the original cost of a bus, communication system, or safety devices installed on the bus. The amount budgeted may not, over time, exceed 150% of the original cost of the bus, communication system, or safety devices. 

(2) Annual depreciation may not exceed 20% of the bus, communication system, or safety devices' original cost.

(3) The cost of new parts added after the original purchase of a bus, communication system, or safety devices may not be depreciated.

(4) The bus depreciation reserve fund shall not be used to depreciate or replace motor vehicles designed to carry ten or fewer persons.

(5) The bus depreciation reserve fund may be used to depreciate and replace "over-the-road" coaches used for student activities and athletics.

(6) The trustees of a district may use the bus depreciation reserve fund to replace or purchase an additional school bus as defined in 20-10-101(4)(a), MCA. Additional buses that do not meet the definition of a school bus in 20-10-101(4)(a), MCA, and that result in expansion of the district's fleet must be purchased from the general, transportation, student activity, or other fund as allowed by law.