Mont. Code Ann. § 61-3-307
61-3-307 Voluntary registration suspension
61-3-307 . Voluntary registration suspension. (1) A person whose vehicle is registered in the state may suspend the registration in a manner prescribed by department rulemaking. If the vehicle is registered to multiple adults, they shall all consent to the suspension.
(2) A vehicle with a suspended registration may not be driven on the ways of this state open to the public.