The Montana Vehicle Code outlines highway safety, driver’s licenses, vehicle equipment and titles and registrations. The code also covers Montana traffic laws including no passing zone violations, driving under the influence (DUI), radar use, reckless driving, special speed zones and hand signals.
Under Montana DUI law, drunk driving is defined by a blood alcohol level (BAC) of .08% or higher. However, if an officer finds your BAC to register between .04% and .08%, you can still be charged with a DUI if other evidence can conclude you are drunk. A first time offender with a BAC between .04% and .08% can face 24 hours in jail and a minimum fine of $300. First time offenders with a BAC of .08% or higher can face up to 10 days in jail and a minimum fine of $300.