Mont. Code Ann. § 61-6-109
61-6-109 Exceptions
61-6-109 . Exceptions. This part shall not apply with respect to any motor vehicle owned by the United States, this state, or any political subdivision of this state or any municipality therein; or, except for 61-6-139 , with respect to any motor vehicle which is subject to the provisions of 69-12-402 , requiring insurance or other security.