Drunk Driving Laws Montana
When it comes to drunk driving and laws relating to it, Montana has very strict regulations in place. There are penalties for the offense and one needs to be aware of them before driving in Montana.
A driver is perceived to be legally drunk under these circumstances in Montana:
- Non-commercial drivers that are aged 21 or over are said to be legally drunk if the alcohol level in their blood is .08 or over.
- Commercial vehicle drivers are said to be legally drunk when the alcohol level in their blood is 0.04 or more.
- Drivers under the age of 21 are considered to be drunk legally when their BAC is 0.02 or over.

Montana drunk driving law: Punishment for drunk driving in Montana
First-time offense
If the offense is committed for the first time, the person will be required to face a prison term of 6 months along with a fine that may range between $300-$1000. The license revocation time for the driver under this condition is 6 months, however, if a passenger aged under 16 was found to be in the vehicle when the offense was committed, the offender will be subjected to a prison term of 12 months along with a fine of $600-$2000.
Second-time offense
A person committing the offense for a second time will face more severe action. He will face a 12-month prison term along with a fine that ranges between $600-$1000. The license revocation time for the driver is 12 months, however, if a passenger under the age of 16 was found to be in the vehicle during the time of this offense, the offender will be subjected to a one-year prison term along with a fine that ranges between $1200-$2000.
DUI laws for the third-time offense
A person charged with DUI for the third time will be required to serve a prison term of one year along with a fine of $1000-$5000. The revocation period for the driver’s license is 1 year, however, if a passenger under the age of 16 was found to be in the vehicle during the time of the offense, the fine will be harder and will range between $2000-$10,000.
Fourth/subsequent offense
DUI laws for subsequent offenses are different. The offender will be required to undergo treatments in a correctional facility for 13 months or attend a residential alcohol treatment program operated by the Department of Corrections, Montana. Moreover, such an offender will also be subjected to a 5-year suspended sentence along with which he/she will be required to pay a fine that ranges between $1000-$10,000. The revocation period for the driver’s license under such conditions is 1 year.
DUI laws for Underage Drunk Driving
Drunk driving is a serious offense in Montana and if the offender is aged under 21 years, his/her driver’s license might be suspended for a blood alcohol level of 0.02% or more. A first-time underage offender’s driver’s license may be suspended for 90 days while it may go up to 6 months for a second offense. For the third offense, the driver’s license will be suspended for one year.
Ignition Interlock
If a person is charged with DUI or drunk driving offense with a blood alcohol level of 0.08% or over, he/she will need to, for a certain time period, install a device for ignition interlock in his/her vehicle. This device will require the person to undergo a BAC test before starting the vehicle.
Revocation of Driver’s License: Requirements
Requirements vary with the severity of the offense but these are certain general things an offender should know:
- Complete alcohol education program
- Pay revocation fee
- Take the knowledge test for a driver’s license
- Submit the required documents