Understanding Missouri’s DUI Laws: BAC Limits, Tests, and Legal Rights

Driving under the influence (DUI) is a criminal offense in the state of Missouri. Missouri law addresses blood alcohol level (BAC), field sobriety testing, and your legal rights during a stop.

What Is Missouri DUI?

DUI is when the driver is too drunk or high to drive safely. They refer to it there in Missouri as DWI (Driving While Intoxicated). It is the same. Police will arrest you if your BAC is or above the limit. Police may arrest you even if your BAC is below the limit, if police are convinced that you are drunk. Swerving, slurred speech, or slow reaction are all it takes. DUI charges are not exclusive to alcohol. They are also used with drugs, even legal drugs. If a drug impacts your driving ability, you will be charged.

BAC Limits in Missouri

Your BAC limit depends on your age and class of license:

21 and older: 0.08%
Commercial drivers: 0.04%
Under 21: 0.02%

If your BAC is over these, you are a violator. Offenders who are repeat offenders get more severe penalties. Even when your BAC is below limit, you may be charged if impaired. Your behavior and test results are what the officer makes decisions about.

How BAC Is Measured

When BAC is administered, it is done in three general ways that officers use:

Breath Test: Most common. You blow into a machine.
Blood Test: More accurate. Used if breath tests are not permitted.
Urine Test: Least frequently, usually when drugs are in question. When.

You can decline a test, but you have a penalty. If so, your license will be revoked.

Implied Consent Law

When you drive a car in Missouri, you agree to submit to a chemical test. That’s “implied consent.”

Failing to take a test can mean:

1-year license suspension (first refusal)
Increased suspension for subsequent refusals

This is separate from any DUI arrest. Even if the charges are dropped, the license action takes place.

Field Sobriety Tests

These are often given before the police give a BAC test. They evaluate balance, eye movement, and coordination with instructions.

Examples of familiar tests:

Walk and turn
One-leg stand
Horizontal gaze test

These tests are not definitive. Medical conditions or anxiety might affect your test results.

You may decline to take these tests, but you can be arrested by police on other charges.

Missouri DUI Penalties

First Offense:

6 months in jail or less
$1,000 maximum fine
90-day license suspension
Ignition interlock device possible

Second Offense:

Maximum 1 year in jail
Fine up to $2,000
1-year license revocation
Ignition interlock required

Third Offense:

Maximum 4 years in jail
Fine of up to $10,000
Denial of license for 10 years

More DUI arrests result in greater fines and time in jail. When there is injury or death, the charges become more severe and become a felony.

Your Legal Rights

You do have rights when you are stopped drunk:

Be silent. You don’t have to answer questions.
Ask for an attorney.
Decline field sobriety tests.
Decline chemical tests, but lose your license.

You don’t have to talk. You don’t have to tell them where you have been and what you have been doing. When you get arrested, just stay calm. Don’t resist. Call a dui defense attorney in Kansas City as soon as possible. Whatever you say can be used against you.

License Suspension and Revocation

If you refuse or fail to take a test, your license is affected:

First failure: 90-day suspension
First refusal: 1-year revocation

You may be eligible for a limited driving license with an ignition interlock device. You can drive to work or school.

To have your license reinstated, you may need to:

Take a Substance Abuse Traffic Offender Program (SATOP)
Show proof of insurance (SR-22)
Pay reinstatement fees

Ignition Interlock Device (IID)

An IID will not allow your vehicle to start if you have been drinking.

Courts will issue one if:

You have more than one DUI
You apply for reinstatement of your license early

You get it installed and pay the monthly charge. You need to blow into the machine each time you drive. Tampering with the IID or having someone else blow into the IID is against the law.

DUI and Minors

Missouri has a “zero tolerance” law regarding driving while intoxicated if you are a minor, under age 21.

If you are under 21 and your BAC is 0.02% or higher:

First offense: 30 days suspension
Second offense: 90 days suspension
You can also be fined, required to serve community service, or required to undergo alcohol education. Parents can be notified.

Minor drivers with a 0.08% or higher BAC are treated as adults and prosecuted for DUI.

DUI and Drugs

DUI isn’t limited to alcohol. DUI under the influence of drugs is illegal as well.

It involves:

Illegal drugs
Prescription drug (if you’re under its effect)
Over-the-counter drug (if you’re under its effect)

Police might have a drug recognition expert examine you. They observe things like your pupils are wide, have a slow reaction, and are slurred. You can be arrested even if you’re prescribed.

What to Do When You’re Under Arrest

Don’t freeze. Keep calm.
Call a DUI lawyer. They know the system.
Request a hearing. You have 15 days to appeal the suspension of the license.
Do as the courts instruct. That’s classes, community service, or use of IID.

Write it down. Be present at all court appearances. Your attorney will guide you. A DUI is serious stuff. Work, insurance, and residence will be impacted.

How to Avoid a DUI

Don’t drink or use drugs prior to driving
Ride with a service or have a friend call you
Sleep over if you need to
Get a sober driver

One drink can slow you down. Plan ahead. It’s cheaper and safer than a DUI.

FAQ: Missouri DUI Laws

1. Can I refuse a breath test in Missouri?

Yes, but your license will be suspended for one year. This is “implied consent.”

2. What if I receive a DUI under 21?

You’ll be suspended from the privilege of a license for 30 days on your first offense. You’re given extra punishment if you’re a repeat offender.

3. Do I have a DUI on marijuana?

Yes. If it makes driving hazardous, you can be charged with a DUI on anything you put into your system, including medicinal or legal marijuana.

4. Will a DUI show up on my record?

Yes. A DUI is a crime. It will be on your record and can affect jobs or insurance.

5. How do I get my license back after a DUI?

You’ll have to serve your suspension, pay fees, and potentially need an IID. An attorney would be able to assist you.

Missouri doesn’t mess around with DUI. Know your limits. Know your rights. Drive safely.

Contact an experienced criminal defense lawyer in Kansas City today.