Driving Under the Influence of Drugs

DUI/DWI charges for driving while high on drugs.

By , Attorney · University of San Francisco School of Law

Public safety is the primary concern of DUI and DWI laws. So it makes sense that these laws apply not only to drunk driving, but also to driving under the influence of drugs. After all, a driver who's high on drugs poses the same sort of threat as a driver who's had too much to drink.

All states have drug DUI laws. But states have taken slightly different approaches with their legislation. This article discusses some of the ways state laws address drugged driving.

Drugged Driving Laws

DUI laws come in two general types: "per se" and "impairment." Impairment DUI laws are based on the actual effect the drugs or alcohol had on the driver. Per se DUI laws, on the other hand, make it illegal to drive with a certain amount of alcohol or drugs in your system. Here's how these two types of laws work in the context of drugged driving.

Impairment Laws

State laws usually prohibit driving while "under the influence" of or "intoxicated" by drugs. But what these terms actually mean differs by state. In some states, a DUI conviction requires proof that the motorist was "substantially impaired" or rendered "incapable" of driving safely. In other states, the prosecution just needs to show the driver was affected in "some" or "any" way by the substance ingested. Some states even have separate offenses that carry different penalties depending on the driver's level of impairment.

Another issue with impairment laws is linking the driver's apparent state of intoxication to narcotics use. Generally, state laws are fairly inclusive in terms of what drugs or controlled substances can lead to a DUI conviction. Some statutes provide exhaustive lists of prohibited substances, while others employ catch-all phrases like "any intoxicating substance."

But a prosecutor can still run into problems unless there's a drug test showing what substances were in the driver's body. Unlike with alcohol, drugs don't always have an identifiable odor. And it's sometimes tricky to determine whether strange behavior is attributable to drug use or mental illness. Driving while in a state of psychosis presents its own problems, but it doesn't qualify as a DUI.

Also, some states have slightly different standards and defenses when it comes to prescription drugs.

Per Se Laws

With a per se DUI charge, prosecutors don't have to worry about impairment: They just need to prove the driver had a prohibited amount of a particular substance in his or her body. Not all states have per se DUI laws that apply to drugs. And among the ones that do, there's no uniform approach.

Some states list prohibited blood concentration levels for common drugs like cocaine, marijuana, and methamphetamine. Other states use a zero-tolerance approach and just make it illegal to drive with any measurable amount of a controlled substance in your body. There are also per se drug DUI laws that impose stricter standards on drivers who are under the age of 21.

A prosecutor's ability to prove a per se DUI charge depends in large part on there being test results showing the amount and type of substance in the driver's body. Implied consent laws require all drivers lawfully arrested for a DUI to submit to testing. So, in most cases, the prosecution will have access to the necessary evidence.

Drug DUI Penalties

Generally, a DUI case can lead to two types of consequences: administrative penalties and criminal penalties. Administrative penalties are imposed by the Department of Motor Vehicles (DMV) after certain DUI arrests. Criminal penalties, on the other hand, are imposed by the court after a DUI conviction.

Administrative Penalties

Most states have "administrative per se" laws that prohibit driving with a blood alcohol concentration (BAC) of .08% or more. For a violation, the DMV generally will administratively suspend the driver's license. Administrative suspensions are trigger by an arrest where a chemical test shows the driver's BAC was above the legal limit. An administrative suspension can occur even if the driver is never convicted of a DUI in criminal court.

However, administrative per se laws generally apply only to alcohol. So, a driver who's arrested for being under the influence of only drugs won't usually have to worry about administrative suspensions.

Criminal Penalties

Every state penalizes DUI convictions differently. However, drug and alcohol DUIs generally receive similar treatment. For a first offense, a defendant might be looking at fines ranging from about $200 to $2,000 and up to a year in jail (though substantial jail time isn't common on a first DUI).

Talk to a DUI Attorney

The consequences of a DUI are serious, and the facts of every case are unique. After being arrested for a DUI, you should get in contact with an experienced attorney. A qualified DUI attorney can explain how the law applies to your case and let you know if you have any viable defenses.

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