What are the changes to Missouri DWI laws in 2026?
On August 28, 2026, a few changes to Missouri’s driving while intoxicated (DWI) laws took effect. For someone already dealing with a DWI arrest, or trying to understand how the new law could affect a family member, that kind of news can raise more questions than answers.
The changes from House Bill 1740 and Senate Bill 1135 are significant, but they don’t affect every DWI case the same way. Some provisions apply only in more serious situations, while others can affect the licensing process or what a driver may need to do before getting back on the road.
That’s why it helps to look at the new Missouri DWI laws in practical terms rather than treating them like one sweeping change. For Missouri drivers and their families, the key is understanding which parts of the law actually apply to the situation in front of them.
Note: This page provides general information and is not legal advice. It should not replace a consultation with a licensed attorney about the facts, deadlines, and legal issues in a specific case.
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New Classifications and Punishments Under Missouri DWI Laws
Some of the biggest changes in these bills affected Missouri’s primary driving while intoxicated law (Revised Statutes of Missouri (RSMo) §577.010). The basic definition of a DWI remains the same, but the changes affected how charges are classified when the incident involves injuries or fatalities:
| DWI caused | Prior charge | New charge | Sentencing* |
| Physical injury to another person | Class E felony | Class D felony | Up to seven years in prison and $10,000 in fines |
| Serious physical injury to another person | Class D felony | Class C felony | 3 to 10 years in prison and up to $10,000 in fines |
| Death of another person | Class C felony | Class B felony | 5 to 15 years in prison |
*Under Missouri’s general sentencing guidelines (RSMo §558.011 and §558.020).
In other words, a driver facing a DWI charge that injured or killed another person can now face more severe punishments, though the sentencing amounts listed above aren’t automatically imposed if someone is convicted under DWI laws in Missouri. Those totals are the maximum potential sentencing a driver can face. A case’s actual outcome can vary based on several factors, such as the evidence, the nature of the injury, the driver’s prior history, and whether prosecutors can prove criminal negligence.
However, some of the changes to RSMo §577.010 now require drivers convicted of a Class B felony under Missouri DWI laws to serve at least five years in prison before becoming eligible for parole or probation. Those convicted of a Class A felony (caused the death of another person and have been previously convicted of a DWI that caused a fatality) must serve 10 years instead.
New Bentley and Mason’s Law
One of the other impacts of these bills is the creation of a new statute (RSMo §454.1050) that imposes a separate financial obligation in certain cases where a DWI (RSMo §577.010) or excessive blood alcohol content (BAC) charge (RSMo §577.012) causes the death of one or both of a child’s parents.
Under the new Bentley and Mason’s Law, when a person is convicted of, pleads guilty to, or enters a nolo contendere plea to a DWI in Missouri or an excessive BAC charge that resulted in a parent’s death and a surviving parent or guardian petitions the court, the driver “…shall be ordered by the court to pay child maintenance.”
Basically, in addition to their criminal sentence, the driver must also make support payments for the child’s livelihood. The court, however, doesn’t simply assign a standard amount. Instead, it considers several factors, including the surviving parent or guardian’s resources, the child’s financial, educational, and emotional needs, and their expected standard of living.
Payments generally continue until age 18, though they can continue longer in some situations, such as educational circumstances or when a child cannot support themselves because of a physical or mental condition. If the driver is initially unable to make payments because they’re incarcerated, the new law also gives them up to one year after release to begin making payments, including arrears.
New Missouri Ignition Interlock Requirements
Another significant change the bills made was to expand when a driver may need to install an ignition interlock device. Ignition interlock devices require drivers to provide a breath sample before they can start their car and drive. While these systems were already part of DWI laws in Missouri, their role has expanded in both court orders and driver’s license reinstatements.
Per the updated RSMo §302.304, §302.440, §302.525, and §302.574, courts may order an ignition interlock system for a first-time intoxication-related driving offense but must require one for second or repeat offenses. Devices are also mandatory for offenses involving a driver with a BAC of at least 0.15%, property damage, or personal injury.
Devices generally must remain installed for at least six months after the driver’s license is reinstated, but if monitoring shows certain alcohol readings, tampering, or circumvention during the final three months, the driver may have to continue using the system for an additional three months without any further violations.
Finally, the expanded statutes also create a discount for drivers who may not be able to afford an ignition interlock device. If the driver’s income is at or below 150% of the federal poverty level, they may qualify for a discount and be responsible for only 10% of the device’s cost. However, additional costs caused by noncompliance aren’t discounted.
A DWI Charge Calls for a Missouri DWI Lawyer
Understanding how these changes affect Missouri DWI laws is one thing; understanding how they can apply to a DWI charge is another. That requires taking a closer look at the facts, evidence, driver’s history, and any related licensing issues.
MRD Lawyers helps clients sort through those details and understand what comes next. Our background as former Greene County prosecutors gives us a practical understanding of how the government is likely to evaluate and handle Springfield and southwest Missouri DWI cases. That perspective helps us identify the issues that can shape the case and explain the options available to you.
If you’re facing a DWI charge in Springfield or southwest Missouri, set up a free consultation today to get a clearer understanding of what you’re facing and what the next steps may look like.