June 5, 2015


DUI drugs cases, often referred to by police as “drugged” driving, have received much more attention in the past few years. As your family members, friends and neighbors take more prescription medications; and the rate of addiction to illegal drugs rises, so does the prosecution of DUI drug cases.

According to a recent study by the Mayo Clinic 70% of Americans are taking prescription drugs. The study also finds that 20% percent of patients are taking five (5) or more prescription medications (maybe you should ask Grandma). How any medication effects you, the duration of its effects, and the severity of any side effects is person specific.   Not everyone responds exactly the same to a drug, at the same dose.

With these numbers in mind, pick any magazine (if magazines are still a thing by the time you read this). You will find an advertisement for a drug being sold at your pharmacy. Look at the back page of the advertisement. There are dozens of potential side effects listed.

Many of the listed side effects can be argued as a sign of impairment by law enforcement. This is true even when the medication is taken everyday to reduce your cholesterol. For the person taking a sleep aid such as Ambien there is a real danger.  The Ambien will still be in your system (and no longer impairing) but the “jitters” observed by a police officer then next day during a traffic is caused by your Lipitor. Drug impairment is apparently in the eye of the beholder.

No reasonable person advocates for the legality of driving while impaired by a drug or medication. Unfortunately, the real issue is the overreach by law enforcement claiming they can systematically detect impairment from a medication or a drug. There cases are usually prosecuted without any legitimate scientific evidence of impairment. The “I know it when I see diagnoses” of impairment has been covered in a cloak of pseudo-science that the would never be accepted by the scientific community outside of “forensics”.


These cases stand directly at the crossroads of where science and law meet. On their face, it would be easy to jump to the conclusion that they are same thing as an alcohol DUI. While the statutes making the underlying conduct illegal appear similar, evaluating the evidence requires a sound understanding of the basic toxicology of the drug(s) at issue.  Once you have this background, you learn the fundamental difference between a DUI based upon alcohol and one based upon drugs.  That is, unlike an alcohol case, in a drug DUI a chemical test cannot tell you anything about whether a person is impaired.

While well settled in the scientific community, the fundamental fact that a chemical test cannot determine impairment is only acknowledged with qualifications by law enforcement in cases where a blood samples is taken.  Specifically, the National Highway Safety Traffic Administration’s training manual provides: “Interpretation of Blood Concentrations: It is difficult to establish a relationship between a person’s the blood or plasma concentration and performance impairing effects.” NHTSA Drugs and Human Performance Fact Sheet, page 8.  However, in case with only urine a urine sample, the manual does recognize: “Interpretation of Urine Test Results: Detection of total THC metabolites in urine, primarily THC-COOH-glucuronide, only indicates prior THC exposure. Detection time is well past the window of intoxication and impairment.” NHTSA Drugs and Human Performance Fact Sheet, page 9.

In addition, while the law may treat a drug based DUI similar to an alcohol DUI, the public certainly feels differently about them. Based upon my experience over the last 15 years with these cases (as both a prosecutor and defense attorney) the public often looks at drugged driving allegations much more skeptically than alcohol cases. This is particularly true for allegations where the police claim you are impaired by a prescription medication and/or marijuana.


Legally, as with alcohol, these cases usually consist of both an “impaired” driving count and a type of per se violation. A typical drug DUI case will start with you receiving two charges alleging that you were driving:

  • While impaired by a drug while driving [A.R.S 28-1381(a)(1)]; and
  • While having an illegal drug or its metabolite in your body [A.R.S 28-1381(a)(3)]

If convicted, the legally required penalties for either count is substantially the same those of an alcohol based conviction. The primary difference is the that a drug DUI conviction can result in more serve consequence for your driver’s license (i.e. 1 year license revocation).


As with alcohol cases, Arizona law makes it illegal to drive while impaired by a drug.  Also similar to an alcohol DUI, our legislature has made a companion charge to the driving while impaired by a drug violation.  This charge is called a per se violation.  Per se meaning  “by itself.”  This part of the law makes it illegal to drive while having a drug (or its metabolite) is in your system regardless of whether it is impairing while driving.

The problem with such charges is they can be legally “absurd.”  As science tells us that the presence of a medication or a drug in your blood does not tell us if you are impaired.   This scientific fact has been the basis for the Arizona Supreme Court to recently overturn several types prosecutions under these per se DUI drug laws.

Impaired By A Drug Or Medication 

If you have ever had outpatient surgery, there is a good chance that you received a pain medication such a Vicodin, Percocet or Oxycodone.  All of the medications have psychoactive (mind-altering) affects. Thus, it would be unwise to attempt most of your daily activities while taking them.  In addition to being unwise, it is also illegal to drive you car while being impaired by any of them.  This is true despite the fact you have a legal prescription to consume the medication.  The prescription does not give you permission to operate a vehicle while under impaired by the medication.

Obviously the same logic and law applies to any illegal drug.

Driving With Prescription Drug – Without A Valid Prescription 

The defense to the per se drug DUI charge is having a valid prescription – not that the medication at issue is a capable of being prescribed.  For example, you spouse may have a prescription muscle relaxer they were prescribed several months ago in your medicine cabinet.  If you injure your back one day and use this medication, this act in and of itself is illegal.  In addition, driving while this medication is in your system is also considered a DUI in Arizona.

Driving With An Illegal Drug In Your System

When you go to your doctor because of nagging pain in your lower neck, it is safe to say that you will not leave with a prescription for methamphetamine. Some drugs are not able to be legally prescribed in Arizona. These commonly called “street drugs.” A few examples of these drugs include:

Driving while any illegal street drug in your system is considered a drug DUI under Arizona law.


Arizona law prohibits not only driving while there is an illegal drug in your body, but also driving with “its metabolite” as well.  Thus, it is important to understand what is and is not “its metabolite.

One of the primary mechanisms by which drugs are cleared from the human body is your metabolism. Through your metabolic system a drug is converted into different chemicals.  These new chemicals are called metabolites.  A drug can be metabolized into a new type of drug.  Some metabolites can be active in the body.  That is, there are some metabolites that can have effects upon you such as impairment even after being processed by your body.

To illustrate, the active ingredient in marijuana is THC.  It is a “drug” prohibited by Arizona’s DUI statute.  When THC is metabolized it produces Hydroxy-THC.  Hydroxy-THC is then further metabolized into something called Carboxy-THC. Carboxy-THC is not capable of causing impairment.

However, for many years, the State of Arizona prosecuted people for merely driving with Carboxy-THC in their systems.  The presented several problems.  First, Carboxy-THC can be in your system weeks after the ingestion marijuana.  Thus the present of this metabolite is not evidence of impairment.    Second, Carboxy-THC is not the metabolite of THC (i.e. marijuana).  Carboxy-THC is essentially the “grandchild” of THC.  It is the metabolite of the metabolite of THC.  From a statutory construction standpoint, the plain language of the DUI laws was singular when referencing metabolite – not plural.  Consequently is statute did not intend to criminal every metabolite down the chain from THC.

In 2014, the Arizona Supreme finally resolved this problem holding that marijuana DUI prosecutions based solely upon the presence of Carboxy-THC were “legally absurd” and barred them.


Most Drug DUI cases involve a blood sample being tested by a machine called a gas chromatograph.  Alcohol cases uses a technique called headspace gas chromatography.  It is an analytical method that combines the features of gas chromatography and mass spectrometry with the purpose of identifying different substances within sample.


As stated above, a chemical test cannot tell you if a person is impaired by a drug.  It is simply beyond the abilities of chemistry.   Thus, this reality presents law enforcement with a problem in the prosecution of DUIs related to drugs.  As a result, they developed their own impairment recognition program.  Law enforcement “Drug Recognition Program” has been the subject of widespread criticism by scientists, scholars and courts as lacking scientific validity.  That is, their “evaluation” do not actually measure what it claims to measure.

developed by police officers from the Los Angeles (California) Police Department in the early 1970s. The officers’ drug recognition methods were officially recognized by the LAPD management in 1979, and adopted by the National Highway Traffic Safety Administration in the early 1980s.

Two sergeants in the Los Angeles Police Department developed the Drug Recognition and Classification Program (“DEC Program”) in 1979.  The ultimate goal of the DEC program was to “help prevent crashes and avoid deaths and injuries by improving enforcement of drug‑ impaired driving violations.” U.S. Dept. of Transp., NHTSA, DRUG EVALUATION AND CLASSIFICATION TRAINING PROGRAM, STUDENT MANUAL at I‑2 (2007) [hereinafter “DEC MANUAL@].

As part of the DEC Program, police officers with no formal scientific training enroll in a 72‑hour course designed to teach them about the characteristics and effects of seven different categories of drugs on all major systems in the human body. These police officers are taught to administer a twelve‑step drug evaluation and classification protocol to subjects suspected of impairment. The entire test lasts approximately 45 minutes to an hour.

At the conclusion of the twelve‑step analysis, the officer is ostensibly able to conclude: (a) whether the subject has been driving while under the influence of a drug or drugs and, if so, (b) what category or combination of categories of drugs is impairing the subject.

The seven categories of drugs are:

  • Cannabis;
  • Central nervous system depressants;
  • Central nervous system;
  • Stimulants;
  • Hallucinogens;
  • Inhalants;
  • Narcotic Analgesics, and
  • Phencyclidine

The twelve steps of the purported evaluation are:

1. A breath alcohol test;

2. An interviewing;

3. Obtaining an initial pulse rate on the subject;

4. Eye examinations;

5. Four divided attention tests (Romberg Balance, Walk and Turn, One Leg Stand, Finger to Nose);

6. Vital signs and a second pulse rate;

7. analyzing the subject’s eyes and pupil size in dark and light conditions and examining the subject’s nose and mouth for evidence of ingestion of drugs;

8. checking the subject’s muscle tone to determine if his muscles are rigid, normal, or flaccid;

9. examining the subject for evidence of injection sites and obtaining a third pulse rate;

10. interrogating the subject about what drugs he has ingested;

11. formulating an opinion about whether the subject is impaired and what categories of drugs are responsible for the impairment; and

12. Toxicological Examination. DEC MANUAL at IV‑2.


The are currently no regulations governing the analysis of urine or blood.  Unlike alcohol, there is no permit required by the State to performa drug quantification test.  One consequence of this lack of regulations is differing “cut-off” levels for the identification of drugs in a blood sample.  Thus, a person who with a blood test showing 3 nano grams of THC could have a much different fate depending the lab doing the testing.  If one lab has a cut off of 5 ng (anything under that is considered too


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Keep reading by clicking here or if all of this has given you headache, you can contact the firm directly by calling (602) 494-3444.

Lawrence Koplow



Arizona Marijuana DUI

Marijuana DUI cases present a real risk of prosecuting people driving while not impaired. A primary reason is legislation that contradicts what science tell us it true about the drug. However, recently much of the scientific reality about marijuana has made its way to a number of higher courts.  This includes the Arizona Supreme Court.  As a result, the current… keep reading »

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