Mont. Code Ann. § 15-70-125

There is a highway nonrestricted account in the state special revenue fund. All interest and penalties collected under this chapter, except those collected by a justice's court, must, in accordance with the provisions of 17-2-124, be placed in the highway nonrestricted account. All interest and income earned on the account must be deposited to the credit of the account and any unexpended balance in the account must remain in the account.