In a Montana parenting plan case, a DUI is evidence about a parent's judgment and alcohol use. It does not decide custody by itself. The court looks at it under the best-interest factors, one of which is chemical dependency or chemical abuse, and it matters most when a child was in the vehicle or when it is not the first. This page explains how the family statutes handle a DUI and how the criminal case feeds into them. It is part of our Montana DUI Guide.
The Best-Interest Factors a DUI Touches
"The court shall determine the parenting plan in accordance with the best interest of the child" and shall consider all relevant parenting factors, which "may include but are not limited to" a list in the statute (MCA § 40-4-212(1)). The ones a DUI is argued under:
- Subsection (1)(g): "chemical dependency, as defined in 53-24-103, or chemical abuse on the part of either parent."
- Subsection (1)(e): the mental and physical health of all individuals involved.
- Subsection (1)(h): continuity and stability of care, which jail time, a suspended license, or treatment can disrupt.
The definition the statute points to is specific. Chemical dependency means "the use of any chemical substance, legal or illegal, that creates behavioral or health problems, or both, resulting in operational impairment," and it includes alcoholism or drug dependency that endangers health, relationships, or public safety (MCA § 53-24-103). A DUI conviction is not that finding. It is one event. But the other parent may argue it is a symptom, and the question becomes what the rest of the evidence shows.
The same list favors contact with both parents: frequent and continuing contact is considered to be in the child's best interest unless the court finds, after a hearing, that contact with a parent would be detrimental (MCA § 40-4-212(1)(l)).
The Orders a Court Can Enter
| Order | Standard | MCA |
|---|---|---|
| Final parenting plan | The court weighs all relevant factors, including chemical dependency or chemical abuse by either parent. | §§ 40-4-212, 40-4-234 |
| Interim parenting plan | Either parent may move for one, supported by an affidavit. The court may act before a hearing in some cases. | §§ 40-4-213, 40-4-220 |
| Emergency order without notice | Available where an emergency in the child's present environment endangers the child's physical, mental, or emotional health. | § 40-4-220(2) |
| Amending an existing plan | Requires a change in the child's circumstances, based on new or previously unknown facts, and that the amendment is necessary for the child's best interest. | § 40-4-219(1) |
| Supervised visitation | May be ordered if the parents agree, or if the court finds the child's physical health would otherwise be endangered or emotional development significantly impaired. | § 40-4-218(2) |
If You Already Have a Parenting Plan
A final plan is not reopened just because something happened. The court may amend it only if it finds, "upon the basis of facts that have arisen since the prior plan or that were unknown to the court at the time of entry of the prior plan, that a change has occurred in the circumstances of the child and that the amendment is necessary to serve the best interest of the child" (MCA § 40-4-219(1)). The parent asking for the change has to file an affidavit, and the court must deny the motion unless the affidavits establish adequate cause for a hearing (MCA § 40-4-220(1)).
Notice whose circumstances the statute refers to: the child's. A DUI that happened on a night the children were with the other parent is an event in the parent's life. To support an amendment, it has to connect to the child, through risk, through a pattern, or through its practical effects on care.
Montana has a faster procedure for certain convictions. If a parent is convicted of a listed crime, such as partner or family member assault or endangering the welfare of children, the other parent may file an objection, and parenting rights are suspended if there is no response within 21 days (MCA § 40-4-219(8)). DUI is not on that list.
Interim and Emergency Orders
While a case is pending, either parent may ask for an interim parenting plan (MCA § 40-4-213). A parent may also ask the court for a temporary order without notice to the other side. Where a previous plan exists, that requires an affidavit showing that "an emergency situation has arisen in the child's present environment that endangers the child's physical, mental, or emotional health and an immediate change in the parenting plan is necessary to protect the child" (MCA § 40-4-220(2)(a)(ii)). If the court grants it, everyone must appear within 21 days to show cause why the interim plan should not stay in place.
A DUI arrest with the child in the car is the kind of fact that appears in those affidavits. If you are served with an order like this, the hearing date is the priority. What you have done since the arrest is usually what the hearing is about.
A Child in the Vehicle
This is where the criminal and family cases overlap most.
- Higher DUI penalties. With a passenger under 16 in the vehicle, the minimum jail time and the fines for a DUI roughly double (MCA § 61-8-1007).
- A possible felony. Criminal child endangerment covers a person who purposely, knowingly, or negligently causes substantial risk of death or serious bodily injury to a child under 14 by operating a motor vehicle under the influence with the child in the vehicle. The maximum is 10 years and a $50,000 fine (MCA § 45-5-628).
Our page on DUI with a crash or a child in the carcovers the charges. In the parenting case, the same facts go directly to the court's concern about safety.
How the Criminal Case Feeds the Parenting Case
- The record is available. The court file is public, and the other side can ask for the police report and video in the family case.
- The assessment. Every DUI conviction requires a chemical dependency assessment, with treatment if it is recommended. See DUI classes, assessment, and treatment. Its conclusion bears on the exact factor the family court is weighing, in either direction.
- Monitoring. Alcohol testing ordered in the criminal case creates a daily record. A clean record is useful evidence, and a missed or failed test is too. See pretrial alcohol monitoring and the 24/7 sobriety program.
- The license. A suspension changes who can drive to school, activities, and exchanges. A probationary license or an ignition interlock may restore some of that. Tell the family court how transportation will work before the other side raises it.
- Your own words. Testimony or sworn statements in one case can be used in the other. Do not file an affidavit about the night of the arrest in the family case without your defense attorney reading it first.
What Courts Tend to Look For Afterward
The statutes do not prescribe a checklist, and judges differ. The evidence that addresses the chemical dependency factor directly is the kind you would expect: a completed assessment, completed treatment if it was recommended, compliance with every court condition, no new incidents, and a workable plan for transporting the children. A parent who has those things is in a different position from one who is still contesting whether there is anything to address.
The steps that help in the parenting case can conflict with the defense of the criminal charge. Starting treatment early, for example, is a decision to make with your defense attorney. That is the reason to bring both cases to the first meeting.
This page explains Montana law in general as of the 2025 Montana Code Annotated. Parenting decisions depend heavily on the facts and the judge. It is not legal advice about your specific case.