Montana DUI With BAC .16+: Aggravated DUI and Probationary License

Montana Code Annotated § 61-8-465 defines aggravated DUI as any DUI with a BAC of .16 or higher, measured within two hours of driving. This is distinct from standard first-offense DUI (BAC .08–.15) in three ways: mandatory minimum jail time doubles from 24 hours to 48 hours, the hard suspension period before probationary license eligibility extends from 45 days to approximately 90 days, and ignition interlock device (IID) duration extends from six months to one year minimum. The .16 threshold is not discretionary. If your blood or breath test came back at .16 or above, the aggravated classification applies automatically—even if this is your first DUI. The Motor Vehicle Division (MVD) and the district court both treat aggravated cases as higher-risk, which affects both your administrative license suspension (ALS) and your ability to petition for a probationary license. Aggravated DUI also carries stiffer fines and longer SR-22 filing periods. Montana requires SR-22 for three years after any DUI conviction, but aggravated cases often trigger higher premiums because insurers classify BAC .16+ as significantly elevated risk. Your SR-22 certificate must remain active for the full three years, even after your probationary license converts to full reinstatement.

For standard first-offense DUI in Montana, the MVD imposes a hard suspension of approximately 45 days before you can petition the district court for a probationary license. At .16 or higher, that hard suspension extends to approximately 90 days. This means you cannot legally drive—even for work, medical appointments, or school—during that initial 90-day window. The hard suspension period is counted from the date your license was confiscated at arrest or the date the MVD mailed the suspension notice, whichever is earlier. If you were arrested on January 1, you cannot petition for a probationary license until approximately April 1. Missing this timeline is the most common mistake aggravated DUI defendants make: filing a petition too early results in automatic denial, and the court will not consider a second petition until the hard suspension period has actually elapsed. If your case involves a breath test refusal in addition to the aggravated BAC charge, the hard suspension period may extend further under Montana's implied consent law. Refusal cases carry an additional one-year administrative suspension that runs concurrently with the DUI suspension, but the court treats refusal as evidence of non-compliance when evaluating probationary license petitions. Most Montana district courts will not grant probationary licenses to refusal cases until the DUI education course is completed and the IID is installed and verified.

Montana Code Annotated § 61-8-442 requires ignition interlock devices for all DUI-related probationary licenses, but aggravated cases trigger a longer minimum duration. Standard first-offense DUI requires IID for six months. Aggravated DUI at .16 or higher requires IID for one year minimum. The device must be installed before the court will issue the probationary license—installation afterward does not satisfy the requirement. Installation costs in Montana typically run $75–$150, with monthly monitoring fees of $60–$90. Over the one-year period, total IID costs range from $900 to $1,200. You pay these costs directly to the IID vendor; the court does not subsidize installation or monitoring. If you cannot afford installation, the court will not grant the probationary license. Financial hardship is not a waiver ground under Montana law. Violating IID terms—failed rolling retests, missed calibration appointments, or tampering—triggers automatic probationary license revocation. The MVD receives real-time data from IID vendors, and most violations result in immediate suspension without a hearing. If your probationary license is revoked for IID non-compliance, you must serve the remainder of your original suspension period before you can petition again, and the court will not consider a second petition favorably.

Montana probationary licenses are issued by district court judges, not by the MVD. You must file a petition in the district court of the county where you reside. Because Montana has 56 counties, petition procedures, filing fees, and hearing timelines vary significantly. Most counties require a $100–$200 filing fee, a proof-of-need affidavit (employment, medical, or school documentation), and an SR-22 certificate at the time of filing. The court schedules a hearing, typically 2–4 weeks after filing. At the hearing, the judge evaluates whether your need is genuine, whether you've completed the hard suspension period, whether the IID is installed and verified, and whether you've enrolled in or completed the required DUI education course. Aggravated DUI cases face stricter scrutiny: judges expect documented proof of employment (paystubs, employer letter), not just an affidavit. Rural counties with limited employers may grant broader route flexibility; urban counties like Yellowstone or Missoula expect specific route maps. If the judge denies your petition, you can file again, but most counties impose a waiting period of 30–60 days before a second petition will be considered. Denial reasons include incomplete documentation, failure to install IID before the hearing, unpaid DUI-related fines, or failure to enroll in the DUI education program. The court will not issue a probationary license if any of these conditions are unmet, regardless of need.

Montana requires completion of a chemical dependency education course or treatment program as a condition of probationary license eligibility for all DUI cases. Aggravated DUI at .16 or higher typically requires a Level II evaluation and treatment program, which is longer and more intensive than the standard Level I course required for BAC .08–.15 cases. Most Montana courts will not grant a probationary license until you provide proof of enrollment and completion of at least the first phase of the program. SR-22 filing is mandatory for all DUI-related probationary licenses in Montana. The SR-22 is a certificate filed by your insurer with the MVD certifying that you carry at least the state's minimum liability coverage: $25,000 bodily injury per person, $50,000 bodily injury per accident, and $20,000 property damage. If you do not own a vehicle, you must obtain non-owner SR-22 insurance, which covers you when driving employer vehicles or borrowed cars under your probationary license. SR-22 filing fees in Montana range from $15 to $50 depending on the carrier, but the premium increase is the real cost. Aggravated DUI drivers in Montana typically pay $140–$240 per month for SR-22 liability insurance, compared to $85–$140 for standard drivers. The SR-22 must remain active for three years from the date of conviction. If your policy lapses for any reason—non-payment, cancellation, or switching carriers without filing a new SR-22—the MVD suspends your license immediately and you lose your probationary license. Reinstatement after SR-22 lapse requires filing a new SR-22, paying a $100 reinstatement fee, and serving any additional suspension period the MVD imposes.

Aggravated DUI at .16 or higher in Montana triggers a multi-layered cost structure. District court filing fee: $100–$200 depending on county. IID installation: $75–$150. IID monthly monitoring for one year: $720–$1,080. DUI education program: $300–$800 depending on whether Level I or Level II treatment is required. SR-22 filing fee: $15–$50. SR-22 premium increase over three years: approximately $2,000–$4,000 above standard rates. MVD reinstatement fee after full suspension expires: $100. Total typical cost: $3,300–$6,400 over the probationary license period and reinstatement timeline. This does not include court fines, attorney fees if you retained counsel, or increased premiums after the SR-22 filing period ends. Aggravated DUI drivers remain classified as high-risk for 3–5 years after conviction, even after SR-22 is no longer required, so premium increases persist beyond the filing period. If you cannot afford the IID installation or SR-22 policy, you cannot obtain a probationary license. Montana does not offer payment plans for IID costs, and insurers will not issue SR-22 policies without upfront payment or down payment. The court will not waive the IID requirement due to financial hardship. If you lose your job during the probationary license period and can no longer afford the IID monitoring fees, the device vendor will report the lapse to the MVD and your probationary license will be revoked.

Montana probationary licenses are not rolling permits. The license is valid for the duration of your suspension period, typically 6–12 months depending on whether this is a first or subsequent offense. Once the suspension period expires, you must apply for full license reinstatement through the MVD. Reinstatement requires proof of SR-22 filing, proof of IID removal (if your IID period has ended), proof of DUI program completion, and payment of the $100 reinstatement fee. If your aggravated DUI required one year of IID and your suspension period was six months, the IID period extends beyond the suspension. You must keep the IID installed and monitored for the full year, even after your probationary license converts to full reinstatement. Removing the IID early triggers immediate license suspension and you lose your driving privilege until the full IID period is satisfied. Your SR-22 filing must remain active for three years from the conviction date, not the reinstatement date. If you were convicted on January 1, 2023, your SR-22 must remain on file until January 1, 2026, regardless of when your license was reinstated. Most Montana drivers do not realize the SR-22 period runs independently of the suspension period. Letting your SR-22 lapse two years after reinstatement will suspend your license again, and you will pay a second $100 reinstatement fee plus any additional suspension days the MVD imposes.