Driving Under the Influence of Marijuana

While marijuana laws have become lax in recent years, a "Marijuana DUI" can still get you in a lot of trouble.

By , Contributing Author

The often tragic consequences and harsh legal penalties for driving under the influence of alcohol are well-publicized. What many people don't realize is that it is also illegal and punishable in all 50 states to drive under the influence of marijuana (or a combination of alcohol, marijuana, or other drugs).

Laws defining what it means to be "under the influence" of marijuana vary by state, as do applicable punishments.

What It Means to Be "Under the Influence"

In most states, being "under the influence" means that the driver is incapable of driving safely due to the effects of drug or alcohol use or has a certain concentration of drugs or alcohol in his or her system.

As you are probably aware, when it comes to alcohol, a blood-alcohol level of .08% or more generally establishes that the driver is under the influence (if the level is less, the prosecutor can still point to the driver's actions to prove that he or she was under the influence). In all states, the blood alcohol level threshold is even lower for drivers who are under 21 years old.

When marijuana is involved, however, states have different approaches to establishing that the driver was under the influence, as shown below.

Per Se DUI Laws

In states with so-called "per se" DUI laws, drivers with a certain amount of marijuana in their system are considered under the influence. States that have per se marijuana DUI laws generally specify a THC (the primary psychoactive ingredient in marijuana) limit. But there are also states that prohibit driving with any measurable amount of marijuana in the blood or urine. Drivers who are at or above the legal THC limit—whether it's a concentration or any measurable amount—can be convicted of a DUI.

Marijuana metabolites—compounds left over when the body metabolizes (or processes) marijuana—can remain in a person's body for days, weeks, or longer after marijuana use. While metabolites indicate that the person ingested marijuana at some point in the past, they do not indicate how long ago or necessarily point to current impairment. Even so, state per se laws that include metabolites accept their presence as conclusive evidence of impairment for the purposes of a DUI charge.

The Driver's Behavior or Driving

Some states don't have per se marijuana laws. In these states, the prosecutor must always establish that the driver was behaving in a way that showed that he or she was under the influence of marijuana at the time of the arrest—regardless of marijuana blood or urine concentration levels. Prosecutors can do this by showing that the driver had impaired balance or speech, or that he was driving erratically—even that he smelled of marijuana.

People are sometimes surprised to learn that the prosecution need not show actual unsafe driving to prove that the driver was under the influence. Merely being under the influence and driving will suffice. For example, suppose you are involved in an accident that you did not cause—your driving was just fine. But the police officer who comes to the accident scene smells marijuana in your car, observes your reddened eyes and tell-tale behavior, and sees half-smoked joints in the ashtray. This may be enough evidence to charge you with driving while under the influence, even though your driving was not unsafe.

Driving as a Medical Marijuana Patient

Many states have made it legal to use marijuana for medicinal purposes, as long as the patient follows the law with respect to amounts, registration, and so on. But no state has gone so far as to say it's okay to drive after using medical marijuana, even when the patient has scrupulously followed the rules. This can be especially problematic for medical marijuana patients in states that employ per se laws because, as explained, metabolites may remain in the body for some time after use, arguably with no effect on the person's driving.

Medical marijuana patients should know how their state approaches the issue of being "under the influence," as explained above.

What Constitutes "Driving": Actual Physical Control

Most state DUI statutes consider someone to be a driver within the meaning of the DUI law when he or she is "in actual physical control" of the vehicle. This definition is broader than our common idea of "driving" or "operating" a vehicle.

Being in actual physical control of the vehicle can include being in control of a parked car. In determining whether a person was in actual physical control of a vehicle, judges and juries tend to consider a combination of factors, including whether:

  • the vehicle was on or off
  • the vehicle was moving or stationary
  • the vehicle was operable
  • the keys were in or out of the ignition (and whether the defendant even had access to the keys)
  • the driver was awake or asleep (was the defendant perhaps "sleeping it off" in a parked vehicle?)
  • there was any gas in the tank
  • the vehicle's gears were engaged, and
  • the defendant was in the driver's seat.

Whether you were in "actual physical control" comes down to the consideration of the specific facts surrounding your case.

Marijuana DUI Penalties

Specific penalties for DUI convictions vary by state, though all states impose some combination of the following to punish DUI convictions:

Within each state, the severity of the applicable penalties in each case usually depends on whether the offense was a first or subsequent violation, and aggravating factors may increase applicable penalties (see below).

Aggravating Factors

The following circumstances may increase the penalties that would normally apply to a DUI conviction:

  • prior offenses
  • a minor in the vehicle at the time of the offense (sometimes referred to as "child endangerment")
  • DUI while driving on a suspended license
  • DUI while driving a school bus
  • causing a traffic accident, property damage, bodily injury, or death, and
  • driving with particularly elevated alcohol or drug content levels.

Sentence Ranges and Mandatory Minimum Sentences

State statutes generally list the minimum and maximum fines, jail time, and license suspension periods for DUI convictions, and the judge gets to decide how to sentence the defendant within those ranges.

In all states, penalties increase for second and subsequent offenses. However, often there's a "wash out" provision—a rule that effectively makes a prior DUI of a certain age go away for purposes of enhancing subsequent sentences. For example, a mandatory minimum may apply to a current conviction only if the prior conviction was incurred less than five, seven, or ten years ago. When a prior has washed out, the subsequent offense is treated as a first offense for punishment purposes.

Get Legal Help for a Marijuana DUI Charge

Driving under the influence of marijuana is a serious charge, even if it is at the misdemeanor level. With this type of conviction on your record, your ability to obtain employment under certain circumstances may be limited. Insurance will become very hard to obtain and your premiums will surely go up. And as you now know, if you are convicted of a DUI again, you will face the possibility of enhanced punishments.

For these reasons, most people will benefit from the assistance of a good criminal defense attorney. Be sure the lawyer you choose has experience with DUI cases in particular—it's a subspecialty, and you'll want a local attorney who knows how these cases are handled by the prosecutors and judges who will be involved in your case.

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