Khalaf & Nguyen has represented numerous clients charged with DUI

An interlock device—more formally called an ignition interlock device (IID)—is a small breathalyzer that’s installed in a vehicle to prevent it from starting if the driver has alcohol in their system.

Here’s how it works:

1. Before starting the car – The driver must blow into the device.
2. Alcohol check – If the breath sample is above a preset blood alcohol concentration (BAC) limit (often 0.02–0.025%), the vehicle will not start.
3. Rolling retests – While driving, the device may randomly require another breath sample to ensure the driver hasn’t started drinking after the car was in motion.
4. Data logging – The device records test results, missed tests, and any tampering attempts, which are usually reported to the court, probation officer, or DMV.

They’re most often ordered in DUI/DWI cases, and in Mississippi, courts can require one for certain offenders as a condition of keeping driving privileges.

Under §63-11-31, a court may order installation and use of an ignition-interlock device for every vehicle operated by a person convicted or non-adjudicated, and each device shall be installed and maintained for the period proscribed by the court.  The ignition-interlock restricted license should be required by the court in a written order.  The device is to be installed prior to the driver being suspended for the DUI conviction or non-adjudication.

A person who installs an ignition-interlock device must obtain an ignition-interlock restricted license.  In order to obtain an ignition-interlock restricted license, a person must be otherwise qualified to operate a motor vehicle and will be subject to all restrictions on the privilege to drive provided by law AND submit proof that an ignition interlock device was installed and is operating on all motor vehicles operated by the person.  Once the ignition-interlock device has been installed, the driver must take the vehicle to the Department of Public Safety for verification that the device was installed in order to obtain the ignition-interlock restricted license.

The following companies install ignition-interlock devices in vehicles in Mississippi. 

You must contact these numbers and tell them your location and they will tell you the nearest location near you.

Alcohol Detection Systems - (888) 205-5431

Intoxalock – (888) 283-5899

Life Safer Superior Interlock Services, Inc. – (800) 377-8750

Smart Start – (800) 880-3394

FEES:

The ignition-interlock fee is to be paid when you obtain your ignition-interlock restricted driving license: $175.00.

Ignition-interlock restricted driver’s license: $56.00

Reinstatement fee to a regular driver’s license after a suspension related to the Implied Consent Law has been served: $175.00

RESOURCES:

MS Dept. of Mental Health – (877) 210-8513

MS Alcohol Safety Education Program (MASEP) – (662) 325-5520

https://www.driverservicebureau.dps.ms.gov/DriverRecords/DUI_Department

1. In Mississippi, an ignition interlock device (IID) is a key part of the state’s DUI penalty system.

2. How the IID-Restricted License Works:

• You must have the IID installed by a state-certified provider.
• Your driver’s license is replaced with an “Interlock Restricted” license.
• You can drive only the vehicle with the IID installed.
• The IID logs every start attempt and rolling retest, and those logs are sent to the court/DMV monthly.

3. Costs and Compliance

• Installation fee: usually $75–$150.
• Monthly monitoring/calibration fee: about $60–$100.
• You must maintain the IID for the full required period, with no missed calibrations or violations

NOTES: The following companies install ignition-interlock devices in vehicles in Mississippi. 

You must contact these numbers and tell them your location and they will tell you the nearest location near you.

Alcohol Detection Systems - (888) 205-5431

Intoxalock – (888) 283-5899

Life Safer Superior Interlock Services, Inc. – (800) 377-8750

Smart Start – (800) 880-3394

FEES:

The ignition-interlock fee is to be paid when you obtain your ignition-interlock restricted driving license: $175.00.

Ignition-interlock restricted driver’s license: $56.00

Reinstatement fee to a regular driver’s license after a suspension related to the Implied Consent Law has been served: $175.00

More Information:  https://www.driverservicebureau.dps.ms.gov/DriverRecords/DUI_Department

Yes — a DUI is very costly, especially in Mississippi, even if it’s your first offense. The direct fines are just the tip of the iceberg; the hidden costs often end up being several times higher.  

• Attorney’s fee
• Alcohol safety education program
• Possible substance abuse assessment
• Any recommended treatment
• Base fine
• Court costs & assessments
• Ignition interlock installation (IID)
• Monthly IID maintenance

MASEP stands for the Mississippi Alcohol Safety Education Program.

It’s a state-mandated program that people convicted of a DUI in Mississippi must complete before getting their license fully reinstated.

Purpose

• To educate drivers about the dangers and legal consequences of impaired driving.
• To reduce repeat DUI offenses by addressing both legal knowledge and alcohol/drug use behavior.

Contact:  MS Alcohol Safety Education Program (MASEP) – (662) 325-5520

The Intoxilyzer 8000 is a type of evidential breath-testing device used by law enforcement to measure a person’s blood alcohol concentration (BAC) from a breath sample.  Some Mississippi law enforcement agencies still use the Intoxilyzer 8000 although the Intoxilyzer 9000 is being distributed throughout Mississippi. Officers must be certified to operate it, and the machine must be regularly calibrated and maintained.

The Intoxilyzer 9000 is a breath-testing device used by law enforcement to measure a person’s blood alcohol concentration (BAC) from a breath sample. It’s an updated version of earlier models like the Intoxilyzer 8000, and it’s currently used by many law enforcement agencies in Mississippi.

This machine will replace the Intoxilyzer 8000 instruments which were purchased more than 20 years ago. The Intoxilyzer 9000 is a modern infrared-based breath alcohol instrument designed for mobile or stationary use. Officers must be certified to operate it, and the machine must be regularly calibrated and maintained. 

Difference from a portable breathalyzer – The Intoxilyzer 9000 is stationary and used at police stations or DUI checkpoints, not handheld in the field. Officers may first use a portable breathalyzer for a preliminary test, then use the Intoxilyzer 9000 for the official evidentiary test.

MADD stands for Mothers Against Drunk Driving.

It’s a nonprofit advocacy organization founded in 1980 by a mother whose daughter was killed by a drunk driver. MADD’s mission is to end impaired driving, support victims of drunk and drugged driving, and prevent underage drinking.

In Mississippi, if you’re convicted of a DUI, the court will order you to attend both MASEP (education) and a MADD Victim Impact Panel (emotional awareness). They’re separate requirements.

Contact:  https://madd.org/mississippi/

Address: 850 E River Pl # 304, Jackson, MS 39202

Phone: (601) 982-5668

Yes, in Mississippi, if you refuse to take a breathalyzer test (including the Intoxilyzer 8000) after being lawfully arrested for DUI, your driver’s license will be suspended under the state’s implied consent laws.

• DUI, 1st offense

Upon conviction of a DUI, 1st offense, a Class R license will be suspended for 120 days, absent a court order for the ignition interlock-restricted license. 

Attendance and completion of the Mississippi Alcohol Safety Education Program (MASEP) is required, along with proof of insurance for three years.  

To continue driving privileges instead of suspension, the court can order the driver to obtain the ignition interlock restricted license. Conditions of the ignition interlock restricted license are imposed under §63-11-31.

CDL holders shall be disqualified from driving a commercial motor vehicle for a period of one (1) year upon conviction of a first violation of operating, attempting to operate, or being in actual physical control of a commercial motor vehicle on a highway with an alcohol concentration of four one-hundredths percent (0.04%) or more, or under the influence as provided in §63-11-30.  A driver can hold only one (1) active credential at a time; Commercial License (CDL) or Regular License (Class “R”).  Suspension time and court D.U.I convictions are determined according to the active license status that Mississippi Department of Public Safety has on file at the time of the traffic offense.      

• DUI, 2nd offense

Upon a second conviction of a DUI, with the offenses being committed within a period of five (5) years, a Class R license will be suspended for 1 year, absent a court order for the ignition interlock restricted license.

• DUI, 3rd offense

Upon a third conviction of a DUI, with the offenses being committed within a period of five (5) years, the offense is classified as a felony, and a Class R license will be suspended for the full period of the person’s sentence. Once released from incarceration, the person will be eligible for only an interlock-restricted license for three (3) years.

• DUI, 4th or subsequent offense

Upon a fourth conviction of a DUI, without regard to the time period within which the violations occurred, the offense is classified as a felony, and a Class R license will be suspended for the full period of the person’s sentence. Once released from incarceration, the person will be eligible for only an interlock-restricted license for ten (10) years.

Per https://www.driverservicebureau.dps.ms.gov/DriverRecords/DUI_Department

• Lapse in Temporary License, 90-day suspension (§63-11-23)

At the time of the offense, the driver’s license should have been seized by a law enforcement officer. A receipt for the driver’s license should then be provided to the driver.  That receipt serves as a temporary permit to drive, and that permit is only valid for 30 days.  When the permit expires, the driver’s license will then be administratively suspended for 90 days, under §63-11-23.  

To stop this suspension from happening, the driver must contact the court, request a trial date, and request an extension of this driving permit.  If no contact with the court is made within 30 days to obtain a court order extending the temporary permit, driving privileges will be suspended for a period of 90 days.

• Refusal of Alcohol Concentration Testing (§63-11-23)

When a person refuses to submit to the chemical testing of that person’s breath, blood, or urine upon request of a law enforcement officer who has reasonable grounds and probable cause to believe a person has been operating a motor vehicle upon the public highways, public roads, and streets of Mississippi while under the influence of intoxicating liquor or any other substance that may impair a person’s mental or physical ability, the person’s Class R license shall be suspended for 90 days. CDL’s shall be suspended for 1 year for a refusal of chemical testing.(§63-1-216)

If the person has previously been convicted or non-adjudicated for a violation of 63-11-30, the person’s Class R license shall be suspended for 1 year.

To avoid a suspension of a Class R license, courts may issue an order to the driver for the ignition interlock-restricted license.

Per https://www.driverservicebureau.dps.ms.gov/DriverRecords/DUI_Department

Suspensions for non-adjudications and convictions shall start 21 days from the date the court order was entered.  

Per https://www.driverservicebureau.dps.ms.gov/DriverRecords/DUI_Department

Any driver who appeals the judgment of either the municipal or justice court where the finding of guilt occurred must provide DPS with the file-stamped “Notice of Appeal” within 30 days of the date of conviction.

Per https://www.driverservicebureau.dps.ms.gov/DriverRecords/DUI_Department

CDL holders who have been suspended for any reason related to a violation of the implied consent law, including a conviction for DUI, remain ineligible to possess a valid CDL during the suspension time. 

Should the CDL holder wish to surrender the CDL and downgrade to a Class R license, the suspension time will continue to run for the CDL. Any provisions of law made available to a Class R license holder remain available to the affected “former” CDL holder. Class “R” or regular license holders that are convicted for D.U.I may obtain a restricted license.

https://www.driverservicebureau.dps.ms.gov/DriverRecords/DUI_Department

A portable breathalyzer is a small, handheld device that law enforcement officers use on the roadside or in the field to estimate a driver’s blood alcohol concentration (BAC) from a quick breath sample. It helps officers decide if there’s probable cause to arrest for DUI. Portable breathalyzers are not as accurate or reliable as evidential breath test machines like the Intoxilyzer 8000/9000. A more accurate, stationary device like the Intoxilyzer 8000/9000 is used for the official test.

Blood Alcohol Content (BAC) is a measurement of the amount of alcohol in a person’s bloodstream.

It’s usually expressed as a percentage—for example, a BAC of 0.08% means there are 0.08 grams of pure alcohol per 100 milliliters of blood.

Key points:

• BAC is used to measure intoxication and is often the legal standard for determining if someone is too impaired to drive.
• In most U.S. states, including Mississippi, the legal driving limit for adults is 0.08% BAC.
• BAC can be measured through a breath test, blood test, or sometimes urine test.
• Factors like body weight, sex, metabolism, food intake, alcohol type, and time since drinking can all affect BAC.

If your driver’s license is suspended or revoked because of a DUI and you keep driving anyway, you’re opening the door to legal trouble.

Mississippi Code Annotated § 63-11-40. Driving while driving license or privilege cancelled, suspended or revoked.

Any person whose driver’s license, or driving privilege has been cancelled, suspended or revoked under the provisions of this chapter and who drives any motor vehicle upon the highways, streets or public roads of this state, while such license or privilege is cancelled, suspended or revoked, shall be guilty of a misdemeanor and upon conviction shall be punished by imprisonment for not less than forty-eight (48) hours nor more than six (6) months, and fined not less than two hundred dollars ($200.00) nor more than five hundred dollars ($500.00).The commissioner of public safety shall suspend the driver’s license or drivingprivilege of any person convicted under the provisions of this section for an additional six (6) months. Such suspension shall begin at the end of the original cancellation, suspension or revocation and run consecutively.

$175.00 Reinstatement Fee DUI / Drug (HB - 1015)

https://www.driverservicebureau.dps.ms.gov/Drivers/Driver_Service_Fees

Field sobriety tests are physical and cognitive exercises that police officers use during a traffic stop to help determine whether a driver may be impaired by alcohol or drugs. They’re typically given after an officer observes signs of impairment—such as erratic driving, the smell of alcohol, or slurred speech.

These tests aren’t the same as a breathalyzer; instead, they assess a person’s balance, coordination, attention, and ability to follow instructions.

The most common Standardized Field Sobriety Tests (SFSTs)—developed by the National Highway Traffic Safety Administration (NHTSA)—are:

1. Horizontal Gaze Nystagmus (HGN) – The officer moves a pen or small object side-to-side and watches the driver’s eyes for involuntary jerking movements that become more pronounced when someone is impaired.
2. Walk-and-Turn – The driver must walk heel-to-toe along a straight line, turn on one foot, and return the same way, all while following instructions exactly.
3. One-Leg Stand – The driver must stand on one leg while counting out loud for a set period, testing both balance and focus.

Important:

• These tests are subjective—officers score them based on their own observations.
• Poor performance doesn’t always mean intoxication; fatigue, medical conditions, injuries, or even anxiety can cause someone to “fail.”
• Drivers are not legally required to take field sobriety tests, though refusing might still lead to arrest if the officer believes there’s probable cause.

1. Right to Remain Silent.

• Mississippi law matches the U.S. Constitution here — you don’t have to answer questions about your drinking, where you were, or other potentially incriminating topics.
• You must hand over your driver’s license, vehicle registration, and proof of insurance.

2.  Right to Refuse the Field Sobriety Tests

• In Mississippi, you can refuse field sobriety tests (walk-and-turn, one-leg stand, HGN/eye test).
• Refusal isn’t a separate criminal offense, but the officer can still arrest you based on other signs (odor of alcohol, slurred speech, erratic driving).

3.  Right to Refuse - Implied Consent for Chemical Testing

• Key Mississippi rule: By driving in Mississippi, you agree to take an Intoxilyzer 8000/9000 breath test, or a blood/urine test, if you are lawfully arrested for DUI.
• You have the right to refuse - Refusal penalties:
• Miss. Code Ann. § 63-11-23(5):
• "a)When sentenced under Section 63-11-30(2):
• (i)For a first offense: one hundred twenty (120) days; (ii)For a second offense: one (1) year;( iii)For a third offense: for the full period of the person’s sentence; upon release from incarceration, the person will be eligible for only an interlock-restricted license for three (3) years; (iv)For a fourth or subsequent offense: for the full period of the person’s sentence; upon release from incarceration, the person will be eligible for only an interlock-restricted license for ten (10) years and will further be subject to court-ordered drug testing if the original offense involved operating a motor vehicle under the influence of a drug other than alcohol."

• Refusal can be used against you in court to imply “consciousness of guilt.”

4.  Right to Ask for an Independent Test

• Mississippi Code § 63-11-13 gives you the right to request an independent chemical test at your own expense, after the state’s test.
• Police must give you reasonable assistance in arranging it.

5. Right to an Attorney

• You can ask to speak to a lawyer after arrest.
• However — Mississippi law doesn’t guarantee that you get to speak to an attorney before deciding whether to take the Intoxilyzer test. You often have to decide right there.g might still lead to arrest if the officer believes there’s probable cause.

 Yes, you have the Right to Ask for an Independent Test

• Mississippi Code § 63-11-13 gives you the right to request an independent chemical test at your own expense, after the state’s test.
• Police must give you reasonable assistance in arranging it.

Miss. Code Ann. § 63-11-13. Right of accused to have test administered by person of his choice; effect of failure to obtain additional test.

"The person tested may, at his own expense, have a physician, registered nurse, clinical laboratory technologist or clinical laboratory technician or any other qualified person of his choosing administer a test, approved by the Mississippi Forensics Laboratory created pursuant to Section 45-1-17, in addition to any other test, for the purpose of determining the amount of alcohol in his blood at the time alleged as shown by chemical analysis of his blood, breath or urine. The failure or inability to obtain an additional test by such arrested person shall not preclude the admissibility in evidence of the test taken at the direction of a law enforcement officer."

Miss. Code Ann. § 45-1-17.  Crime detection and medical examiner laboratory.

"The commissioner shall have the authority to establish, staff, equip and operate a crime detection and medical examiner laboratory, and to cooperate with the University Medical Center and other hospitals and laboratories in its operation."

 In Mississippi, the Zero Tolerance for Minors law is a special DUI rule that applies to drivers under age 21.

Core Rule

• For minors, the legal BAC limit is 0.02% — far lower than the 0.08% limit for adults.
• Even a small amount of alcohol can trigger a DUI charge, because the state wants to discourage any drinking and driving by those under 21.

Miss. Code Ann. § 63-11-30(3) Zero tolerance for minors.

• (a) This subsection shall be known and may be cited as Zero Tolerance for Minors. The provisions of this subsection shall apply only when a person under the age of twenty-one (21) years has a blood alcohol concentration of two one-hundredths percent (.02%) or more, but lower than eight one-hundredths percent (.08%). If the person’s blood alcohol concentration is eight one-hundredths percent (.08%) or more, the provisions of subsection (2) shall apply.
• (b)(i) A person under the age of twenty-one (21) is eligible for nonadjudication of a qualifying first offense by the court pursuant to subsection (14) of this section.(ii) Upon conviction of any person under the age of twenty-one (21) years for the first offense of violating subsection (1) of this section where chemical tests provided for under Section 63-11-5 were given, or where chemical test results are not available, the person shall be fined Two Hundred Fifty Dollars ($250.00); the court shall order the person to attend and complete an alcohol safety education program as provided in Section 63-11-32 within six (6) months. The court may also require attendance at a victim impact panel.
• (c) A person under the age of twenty-one (21) years who is convicted of a second violation of subsection (1) of this section, the offenses being committed within a period of five (5) years, shall be fined not more than Five Hundred Dollars ($500.00).
• (d) A person under the age of twenty-one (21) years who is convicted of a third or subsequent violation of subsection (1) of this section, the offenses being committed within a period of five (5) years, shall be fined not more than One Thousand Dollars ($1,000.00).
• (e) License suspension is governed by Section 63-11-23 and ignition interlock is governed by Section 63-11-31.
• (f) Any person under the age of twenty-one (21) years convicted of a third or subsequent violation of subsection (1) of this section must complete treatment of an alcohol or drug abuse program at a site certified by the Department of Mental Health.

Here’s how 11-nor-9-carboxy-delta-9-tetrahydrocannabinol (often abbreviated “THC-COOH”) fits into a DUI “other” situation in Mississippi:

What It Is

• 11-nor-9-carboxy-delta-9-THC (THC-COOH) is the main inactive metabolite of marijuana (delta-9-THC).
• It is what the body produces after breaking down the psychoactive THC.
• Unlike delta-9-THC, THC-COOH does not cause impairment — it just shows past marijuana use.
• It can remain in urine for days to weeks after use, depending on frequency.

How It Relates to DUI "Other" 

• Mississippi has a DUI statute that covers alcohol, controlled substances, and "other substances" that impair driving ability.
• A DUI “other” charge typically refers to drugs (illegal, prescription, or otherwise) that impair a driver.
• To convict under DUI–other, the State must prove impairment at the time of driving, not just the presence of a metabolite.

Key Issues

• Since THC-COOH is non-impairing, its detection in a blood or urine test does not prove impairment.
• Prosecutors often need:
  • Active THC (delta-9-THC) levels in blood, plus
  • Observations of impairment (driving behavior, field sobriety tests, officer testimony).
• If only THC-COOH is found (with no delta-9-THC), the argument will be that  there’s no evidence the driver was actually impaired at the time.

In short

• 11-nor-9-carboxy-delta-9-THC is just the inactive metabolite of marijuana. In Mississippi, its presence alone in a DUI “other” case may show marijuana use sometime in the past, but it does not prove impairment while driving — which is what the law requires for a conviction..

Mississippi DUI Statute

The main law is Miss. Code Ann. § 63-11-30. It makes it unlawful for a person to drive if they are:

1. Under the influence of intoxicating liquor (alcohol),
2. Under the influence of any other substance that has impaired the driver’s ability to operate a motor vehicle,
3. Under the influence of any drug or controlled substance, or a combination of substances, impairing driving ability,
4. Having a blood alcohol concentration (BAC) of .08% or more (for adults), or
5. For minors (under 21), a BAC of .02% or more.

Marijuana and THC Metabolites

• Mississippi does not have a “per se” THC limit (like Colorado or Washington do).
• Instead, the State must show:
  • The driver was “under the influence” — meaning their ability to drive was impaired.
  • That impairment was caused by a drug or other substance.
• THC-COOH (11-nor-9-carboxy-THC) is only an inactive metabolite. It shows past marijuana use but cannot by itself prove impairment.
• For a DUI–other based on marijuana, prosecutors need:
  • Active THC (delta-9-THC) levels in blood (not just urine metabolites), AND/OR
  • Officer testimony: bad driving, failed field sobriety tests, slurred speech, etc.

Defense

• If the only chemical evidence is THC-COOH in a urine test, Khalaf & Nguyen will argue:
  • The metabolite is non-psychoactive, so it cannot impair driving.
  • Mississippi law requires proof of impairment “at the time of driving,” not just historical use.

Bottom line

In Mississippi, “DUI–other” covers impairment from drugs (including marijuana). But 11-nor-9-carboxy-delta-9-THC alone is not enough for conviction, since it doesn’t cause impairment. Prosecutors must connect drug use to actual impairment while driving.

Case Law

"Proof that a driver was under the influence, as defined by this Court in Leuer, is proof of impaired driving ability for purposes of subsection (b) of the statute. The same holds true for subsections (a) and (c). See Gilpatrick, 991 So. 2d at 133 (holding so for common law DUI under subsection (a)). Notwithstanding any past belief by the bench and the bar to the contrary, subsection (b) does not require an extra element of proof or provide a heightened standard for demonstrating a violation of Section 63-11-30."

Valentine v. State, 322 So. 3d 417, 428 (Miss 2021)

The National Highway Traffic Safety Administration (NHTSA) 2017 report is one of the big government resources courts and lawyers cite when it comes to marijuana and driving impairment.

NHTSA 2017 REPORT: MARIJUANA IMPARIED DRIVING - A REPORT TO CONGRESS

Key Findings:

Detection vs. Impairment

• The presence of THC in blood or metabolites in urine does not reliably indicate impairment.
• Unlike alcohol (where BAC correlates well with impairment), there is no clear threshold of THC that can predict driving impairment.

Pharmacology of THC

• Delta-9-THC (active compound): Impairing effects are short-lived (usually within a few hours).
• 11-nor-9-carboxy-THC (THC-COOH): This is non-psychoactive and can stay in the body for days or weeks after use — but has no correlation to impairment.

Performance Effects

• Some studies show marijuana can impair attention, tracking, reaction time, and coordination.
• However, the degree of impairment varies widely between individuals.
• Experienced users may show less measurable impairment, while inexperienced users show more.

No Per Se Limit

• Unlike the 0.08% BAC limit for alcohol, NHTSA concluded that a per se THC limit is not scientifically supportable.
• Different people with the same THC blood level may be unimpaired or significantly impaired.

QUOTE FROM NHTSA REPORT, PAGE 13 AND 14

"Thus, there are currently no evidence-based methods to detect marijuana-impaired driving. Marijuana has some regularly reported effects on driving related skills that might lend themselves to the development of marijuana-impaired driving detection techniques, similar to those that have been developed for alcohol-impaired driving (Harris, 1980 and Stuster, 1997). However, many of these effects can also be caused by alcohol, other drugs and driver conditions and activities like distraction, drowsiness, and illness. It is not possible to predict whether there might be a unique combination of cues that could be used by law enforcement to detect marijuana-impaired driving with a high degree of

accuracy. Such a method would need to have an extremely low false positive rate (incorrectly identifying a driver as marijuana-impaired when they are not) to be useable by law enforcement.

Feasibility of Developing an Impairment Standard for Drivers under the Influence of Marijuana

Currently, there is no impairment standard for drivers under the influence of marijuana. Many of the reasons for this are discussed elsewhere in this report. They include the fact that there is no chemical test for marijuana impairment, like a BAC or BrAC test for alcohol that quantifies the amount of alcohol in their body, indicates the degree of impairment, and the risk of crash involvement that results from the use of alcohol. The psychoactive ingredient in marijuana, delta-9-tetrahydrocannabinal (THC), does not blood or oral fluid within a short enough time for high THC levels to be detected. As was mentioned

peak THC levels have declined 80% - 90%.

Devices Capable of Measuring Marijuana Levels in Drivers

Conviction on a Driving Under the Influence of Drugs (DUID) charge, or evidence that marijuana played a role in a crash, typically requires evidence that the driver was impaired by marijuana at the time of arrest or the crash. While alcohol concentration (BAC or BrAC) is an accurate measurement of alcohol impairment of driving, the presence of THC in the driver’s body has not been shown to be a reliable measure of marijuana impairment of driving.

Traditionally, measurement of marijuana use by drivers has involved testing biological specimens for the presence of THC (typically blood samples, though urine and other substance have been used). As was stated previously, this testing can take days, weeks, or months before the results are available to law enforcement. The tests take a few hours or less to conduct, but large backlogs in many State laboratories conducting the testing can result in long delays before results are available. Such tests not only indicate whether THC was present in the sample tested, they also quantify the concentration or amount of THC

detected. These toxicological tests confirm presence of THC but they do not indicate driver impairment or necessarily indicate recent marijuana use (when the THC levels are low)."

That’s an important question — here’s how it works in Mississippi:

Medical Marijuana and Driving in Mississippi

1.  Legal to Use, but not to Drive Impaired

• Having a Mississippi medical cannabis card allows you to legally possess and use medical marijuana under the state’s program.
• But the law does not allow you to drive while impaired by marijuana (or any drug).
• Miss. Code Ann. § 63-11-30 makes it illegal to operate a vehicle if you are “under the influence of any drug or other substance” that impairs your ability to drive.

2. No "Per Se" THC Limit

• Mississippi does not have a set THC blood limit like alcohol (.08 BAC).
• This means you can’t be automatically convicted just because you have THC in your system.
• However, if an officer believes your driving is impaired — swerving, failing sobriety tests, slow reaction — you could be arrested and charged with DUI–other.

3. Medical Marijuana Card Does Not Equal Immunity

• Your medical marijuana card is not a defense to a DUI charge.
• Even though your marijuana use is lawful, driving under its influence is still illegal.
• Think of it like prescription medication: you can legally take it, but if it impairs your driving, you can still be charged with DUI.

4.  THC-COOH vs. Active THC

• A urine test that shows only THC-COOH (inactive metabolite) does not prove impairment.
• But if a blood test shows active THC (delta-9-THC) and there’s officer testimony about bad driving or impairment, the State can use that against you.

Bottom Line 

Yes, you can drive in Mississippi if you are a registered medical marijuana patient — but only if you are not impaired.

• The card protects you from being arrested for possession, but not from DUI laws.
• If you drive while impaired, you can still be arrested and convicted.

Miss. Code Ann. § 41-137-5.  Authorization to use medical cannabis; requirements.

(1) No person shall be authorized to use medical cannabis in this state unless the person (a) has been diagnosed by a practitioner, with whom the person has a bona fide practitioner-patient relationship within his or her scope of practice, as having a debilitating medical condition for which the practitioner believes, in his or her professional opinion, that the person would likely receive medical or palliative benefit from the medical use of medical cannabis to treat or alleviate the person’s debilitating medical condition or symptoms associated with the person’s debilitating medical condition, (b) has received a written certification of that diagnosis from the practitioner, and (c) has been issued a registry identification card from the MDOH under Section 41-137-23. A person who has been diagnosed by a practitioner as specified in paragraph (a) of this subsection shall be a qualifying patient, and the practitioner who has diagnosed the patient shall document that diagnosis with a written certification. However, nothing herein shall require a practitioner to issue a written certification. (2) A written certification shall: (a) Affirm that it is made in the course of a bona fide practitioner-patient relationship; (b) Remain current for twelve (12) months, unless the practitioner specifies a shorter period of time; (c) Be issued after an in-person assessment of the patient by a practitioner, or after a telemedicine evaluation for patients who are homebound or bedbound as certified by a practitioner with whom the patient has a bona fide practitioner-patient relationship within his or her scope of practice other than the practitioner making the written certification. For purposes of this paragraph (c), an individual is homebound or bedbound if such individual is physically unable to leave his or her residence without another person’s aid because the individual has lost the capacity of independent transportation due to a medical, physical, or mental health condition or infirmity as documented in writing by a practitioner who has a bona fide practitioner-patient relationship with the patient; (d) Only be issued on behalf of a minor when the minor’s parent or guardian is present and provides signed consent; and (e) Be limited to the allowable amount of cannabis in a thirty-day period. (3) No state agency, department, political subdivision or board shall require a practitioner to require a patient to submit to a drug test as a condition to receiving a certification for a registry identification card. However, a practitioner may require a drug test from a patient that is within his or her scope of practice. (4) After a practitioner has issued a written certification to a qualifying patient, a practitioner may assist the patient in registering for a registry identification card with the Department of Health, in a manner provided by regulations of the Department of Health. (5) After a qualifying patient receives a written certification from a practitioner, the patient shall be required to make a follow-up visit with the practitioner not less than six (6) months after the date of issuance of the certification for the practitioner to evaluate and determine the effectiveness of the patient’s medical use of medical cannabis to treat or alleviate the patient’s debilitating medical condition or symptoms associated with the patient’s debilitating medical condition. Qualifying patients may make a follow-up visit with a different practitioner than the practitioner who originally issued their written certification, provided that such practitioner is otherwise registered and acting within their scope of practice and the provisions of this chapter. (6) Before dispensing medical cannabis to a cardholder, the dispensary from which the cardholder is obtaining medical cannabis shall verify the identity of the cardholder and the authority of the cardholder to use medical cannabis as provided in Section 41-137-39 and shall determine the maximum amount of medical cannabis that a cardholder is eligible to receive and the amount of medical cannabis that the cardholder has received from all dispensaries during a specified period of time using the statewide seed-to-sale tracking system under Section 41-137-11. (7)(a) A practitioner shall be registered to issue written certifications to qualifying patients by completing the required application process as set forth by the MDOH. The MDOH shall require a practitioner to complete a minimum of eight (8) hours of continuing education in medical cannabis in order to issue written certifications. After the first year of registration, these practitioners shall complete five (5) hours of continuing education in medical cannabis annually to maintain this registration. (b) A practitioner shall not be required to have any additional qualifications to be authorized to certify a qualifying patient for a registry identification card, other than such requirements for practitioners as provided under the Mississippi Medical Cannabis Act. (c) A practitioner shall not be required to be registered to certify patients with any state agency or board other than the MDOH. (8) Only physicians and doctors of osteopathic medicine may issue written certifications to registered qualifying patients who are minors. (9) The requirements of this section shall not apply to a person who is authorized to purchase topical cannabis provided under Section 41 137 39(22), and such persons may possess and use such products without being in violation of this chapter.

Miss. Code Ann. § 41-137-5

Mississippi Medical Cannabis Act and Driving

The law is codified mainly at Miss. Code Ann. § 41-137-1 et seq.

1.  No Immunity for Driving Under the Influence

• This makes it crystal clear: even with a medical cannabis card, you cannot drive while impaired by marijuana.

2. No Protection Against DUI Arrest

• The Act says that a person with a medical marijuana card is not subject to criminal penalties for lawful use/possession.
• BUT: It specifically states that this protection does not extend to DUI charges.

3.  Employer and Workplace Rules

• The Act also allows employers to prohibit use or impairment on the job.
• So, having a card doesn’t prevent consequences if you’re impaired at work or while driving a company vehicle.

4. How This Interacts with DUI Laws

• DUI laws remain in full effect (Miss. Code Ann. § 63-11-30).
• The State still has to prove impairment while driving.
• That proof usually comes from:
  • Officer observations (driving behavior, field sobriety tests),
  • Blood tests showing active THC,
  • Other evidence of impairment.

Bottom Line: 

The Mississippi Medical Cannabis Act allows legal medical use, but it:

• Does not authorize driving under the influence.
• Does not shield you from DUI arrest or prosecution.
• Works the same way as prescription meds: legal to use, illegal to drive impaired.