Missouri changed its DWI death law on Aug. 28, 2026. The new law, House Bill 1740, raised the felony class for drunk or drugged driving crashes that hurt or kill someone. It also added mandatory prison time before probation or parole. If you or someone you love is under investigation after a fatal crash in St. Louis, the date of the crash now matters a great deal.
Quick answer: Under the Missouri DWI death law in section 577.010, causing a death through criminal negligence while intoxicated is now a Class B or Class A felony. A Class B conviction requires at least five years in prison before probation or parole. A Class A conviction requires at least ten. These rules apply to crashes on or after Aug. 28, 2026.
What changed in the Missouri DWI death law?
HB 1740, sometimes called Melanie’s Law, moved every injury level up one felony class. It also created a new Class A level for DWI deaths. The table below compares the old and new classes under section 577.010.
| Result of the crash | Before Aug. 28, 2026 | On or after Aug. 28, 2026 |
|---|---|---|
| Physical injury to another person | Class E felony | Class D felony |
| Serious physical injury to another person | Class D felony | Class C felony |
| Death of another person | Class C felony | Class B felony, 5 years before probation or parole |
| Death (new Class A level), or a later DWI after a prior DWI-death conviction | Did not exist | Class A felony, 10 years before probation or parole |
The prison ranges come from section 558.011. A Class A felony carries 10 to 30 years or life. A Class B felony carries 5 to 15 years. See our guide to Missouri felony classes for the full chart.
When is a DWI death a Class A felony?
The statute lists two routes to Class A:
- While driving intoxicated, the driver acts with criminal negligence and causes the death of any person.
- The driver already has a DWI-death conviction and is found guilty of another DWI.
The first route uses nearly the same words as the Class B offense. News coverage of the bill described Class A as the charge for aggravated cases. Until Missouri appeals courts interpret the new language, expect prosecutors to argue for Class A in the most serious cases. A defense lawyer will push back on which subdivision fits the facts.
What does “criminal negligence” mean in a DWI death case?
Intoxication alone is not enough. The State must also prove the driver acted with criminal negligence and that this conduct caused the death. Criminal negligence means failing to see a substantial risk that a reasonable person would have seen.
That gives the defense room to work. Common issues include:
- Whether the driver was actually intoxicated, and how the blood or breath test was taken
- Whether the other driver, road design or weather caused the crash
- Whether the crash reconstruction holds up
- Whether police had a warrant or valid consent for a blood draw
Our page on DWI resulting in death covers these defenses in more depth.
Does the new law apply to crashes before Aug. 28, 2026?
No. A criminal law cannot increase the punishment for conduct that happened before the law took effect. A crash on Aug. 27, 2026 or earlier is charged under the old classes. For a fatal crash, that is the difference between a Class C felony (3 to 10 years) and a Class B or A felony with mandatory prison time.
What other DWI changes came with HB 1740?
The same bill made several other changes that took effect Aug. 28, 2026:
- Bentley and Mason’s Law. A surviving parent or guardian can ask the court to order child maintenance from a driver convicted of a DWI that killed the child’s parent.
- Ignition interlock. An ignition interlock device is now required for reinstatement after an offense with a BAC of .15 or higher, or one involving property damage or injury, under section 302.574.
- Limited driving privilege. A limited driving privilege cannot issue in those cases until proof of a working interlock is on file with the Department of Revenue.
The bill also lowered interlock costs for drivers at or below 150% of the federal poverty level.
What should you do if you are under investigation for a fatal DWI crash?
Do not give a statement to police or an insurance adjuster before talking to a lawyer. Fatal crash cases often take weeks to charge, because police wait for blood results and a reconstruction. That time is your chance to preserve video, phone records, vehicle data and witness names.
These cases are also often charged alongside other counts, such as hit and run or aggravated felony DWI. Read more about when a DWI becomes a felony in our post When Is a DWI a Felony in Missouri?
Frequently asked questions
Is a DWI death a Class A felony in Missouri now?
It can be. Under the 2026 Missouri DWI death law, a DWI death is at least a Class B felony and can be charged as a Class A felony. Class A requires at least 10 years in prison before probation or parole.
What is the minimum sentence for a DWI death in Missouri?
For crashes on or after Aug. 28, 2026, a Class B conviction requires at least five years in prison before probation or parole. A Class A conviction requires at least ten.
Is DWI manslaughter the same as DWI resulting in death?
People use both terms for the same kind of case. Missouri charges it under the DWI statute, section 577.010. See our page on DWI manslaughter.
Can a fatal DWI charge be reduced?
Sometimes. Problems with the blood test, the cause of the crash or the reconstruction can lead to a lesser charge or a dismissal. Every case turns on its facts.
Talk to a St. Louis lawyer about the Missouri DWI death law
A fatal crash charge under the new Missouri DWI death law can mean a decade or more in prison. Brian J. Cooke defends felony DWI and DWI death cases in St. Louis City, St. Louis County, St. Charles County and surrounding counties. Learn more about our St. Louis DWI defense lawyer services, call (314) 439-8501, or contact us online.
This post gives general information about Missouri law as of October 2026. It is not legal advice and does not create an attorney-client relationship.
View All Blogs
