Missouri's driving while intoxicated (DWI) laws prohibit the operation of a vehicle while under the influence of alcohol, drugs, or any combination thereof. This article explains what substances and conduct can lead to a DWI charge and what penalties the offender faces for a conviction.
Missouri statutes don't explicitly define the level of impairment needed for a DWI conviction but do clearly define what substances can be considered.
Intoxication. Missouri doesn't have a clearly defined standard of impairment for DWI charges—the laws just say it's illegal to drive in an "intoxicated condition," which means being under the influence of alcohol, drugs, or a combination of the two. And, unlike some other states, Missouri doesn't have a per se limit on drug metabolites (similar to the .08% alcohol limit). So, to prove a drug DWI charge at trial, prosecutors might present evidence of intoxication such as the officer's observations of things like slurred speech or poor field sobriety test performance and blood test results showing what drugs were in the driver's system.
Impairing substances. Missouri's DWI statutes define drugs as any schedule I-V controlled substance. This category includes street drugs like marijuana, prescription drugs like morphine, and non-prescription drugs like pseudoephedrine. The fact that the offender had a prescription or a medical marijuana card authorizing the use of the drug isn't a defense to an intoxicated driving charge.
The penalties for a drugged driving conviction depend on the number of prior convictions the offender has and a number of other factors.
A first offense is generally a class B misdemeanor and carries up to six months in jail and a maximum of $1,000 in fines. A first offense conviction also generally results in a 30-day license suspension and a 60-day ignition interlock device (IID) license restriction (or 90 days with a restricted IID license).
A second offense within five years or a first offense involving a passenger who's under the age of 17 is a class A misdemeanor. A conviction generally carries ten days to one year in jail, up to $2,000 in fines, and license suspension or revocation (a one-year revocation for a second offense within five years). Second offenders must have an IID for at least six months following license reinstatement.
All DWI offenders must complete a substance abuse traffic offender program. Repeat offenders may be subject to inpatient treatment requirements. However, in some cases, the court can order treatment in lieu of the otherwise required minimum jail time.