Montana · DUI · Checked October 2026
Ignition Interlock Rules in Montana
Ignition Interlock Rules in Montana: What Are the Rules?
When Montana requires an ignition interlock after a DUI.
- First offense
- Discretionary: the court may order it
- Repeat offenses
- For a second or subsequent offense the court must order the 24/7 sobriety program, an interlock restriction (if a probationary license is recommended), or vehicle forfeiture
First Offense in Montana
discretionary: the court may order it
Repeat Offenses in Montana
for a second or subsequent offense the court must order the 24/7 sobriety program, an interlock restriction (if a probationary license is recommended), or vehicle forfeiture
How the Program Works in Montana
the offender pays the device costs; driving while required to use an interlock makes a new DUI aggravated
More on DUI Law in Montana
See the full overview of DUI laws in Montana and read about how ignition interlock programs work.
This page summarizes Montana law from official sources, checked October 2026. It isn't legal advice; a lawyer licensed in Montana can advise on your case.
Frequently Asked Questions
Is an Ignition Interlock Required for a First DUI in Montana?
discretionary: the court may order it
Is an Interlock Required for Repeat Offenses?
for a second or subsequent offense the court must order the 24/7 sobriety program, an interlock restriction (if a probationary license is recommended), or vehicle forfeiture