Drug Recognition Experts in North Carolina: The 12-Step DRE Evaluation Explained

Drugged driving · Expert evidence

A drug recognition expert (DRE) is a police officer with advanced training who performs a standardized 12-step evaluation to decide whether a driver is impaired by drugs and, if so, which of seven drug categories is most likely responsible. In North Carolina, a DRE who holds a current certification from the Department of Health and Human Services may give that opinion to a jury as expert testimony under Rule of Evidence 702(a1)(2). That makes the DRE one of the most important witnesses in a drugged-driving case, and one of the most important to examine closely: what the evaluation can show, what it cannot, and whether it was actually done the way the protocol requires.

Training and DRE-count figures: Beirness & Porath, AAA Foundation for Traffic Safety (Feb. 2019).

What is a drug recognition expert in North Carolina?

A drug recognition expert is a law enforcement officer trained and certified under the Drug Evaluation and Classification Program (DECP). The program began in the 1970s with Los Angeles police officers, was officially recognized by the LAPD in 1979, held its first DRE school in 1980, and was later formalized with the National Highway Traffic Safety Administration (NHTSA). National minimum standards for training, certification and recertification were adopted in 1992, and the program is now governed by the Highway Safety Committee of the International Association of Chiefs of Police (IACP). In North Carolina, DRE certification is issued by the Department of Health and Human Services (DHHS), and the certification is what Rule 702(a1)(2) looks for.

The AAA Foundation’s 2019 program review describes the path to certification: 72 hours of instruction in drug influence evaluation, a comprehensive examination, and field certification that involves evaluating at least 12 subjects. To stay certified, a DRE must complete at least four evaluations and eight hours of approved recertification training every two years. Those records matter, because North Carolina’s rule requires a current certification.

A DRE is usually called when a driver seems impaired but the breath result does not explain it, for example a 0.00 or 0.03 on the Intox EC/IR II from a driver who struggled on the roadside tests. For background on drug DWIs generally, see our guides to prescription-medication DWI, marijuana and THC and DWI cases without a breath test.

1. 1970sLos Angeles officers begin developing a systematic way to recognize drug impairment.
2. 1979–1980The LAPD officially recognizes the protocol; the first DRE school is held in Los Angeles.
3. 1992National minimum standards for the program are adopted; the IACP’s Highway Safety Committee governs it.
4. 2006North Carolina adds Rule 702(a1), including the DRE provision, through S.L. 2006-253.
5. 2011S.L. 2011-283 amends Rule 702(a) to the federal Daubert reliability standard, later confirmed in State v. McGrady (2016).
6. 2018State v. Fincher: no separate reliability foundation is needed for the DRE method itself.
7. 2025State v. Moore (July 16): the DRE must still have reliably applied the protocol to the actual defendant.

Sources: AAA Foundation (2019); Rule 702 history note, ncleg.gov; UNC School of Government, NC Criminal Law blog (Sept. 3, 2025).

The 12-step DRE evaluation, step by step

The DRE protocol is a fixed sequence, done in person and recorded on a standardized face sheet. The IACP names the 12 steps as follows, and each one produces evidence that can be checked.

1. Breath alcohol test

   The arresting officer reviews the breath alcohol result and asks whether the driver’s impairment is consistent with it. If it is not, a DRE evaluation may be requested. In North Carolina the evidential breath test is governed by G.S. 20-139.1.

2. Interview of the arresting officer

   The DRE reviews the breath result and asks the arresting officer about the subject’s behavior, appearance and driving.

3. Preliminary examination and first pulse

   Standard health and ingestion questions (food, alcohol, drugs, prescriptions); observations of attitude, coordination, speech, breath and face; a check of pupil size, eye tracking and an initial HGN check; and the first pulse. If a medical problem is suspected, the DRE is supposed to seek medical help.

4. Eye examination

   Horizontal gaze nystagmus (HGN), vertical gaze nystagmus (VGN) and lack of convergence. See our guide to the HGN eye test.

5. Divided attention psychophysical tests

   Four tests: the Modified Romberg balance, walk and turn, one-leg stand, and finger to nose. Two of these, walk and turn and one-leg stand, come from NHTSA’s standardized field sobriety tests.

6. Vital signs and second pulse

   Blood pressure, body temperature and the second pulse.

7. Dark room examinations

   Pupil size is estimated with a pupilometer under three lighting conditions to judge whether pupils are dilated, constricted or normal.

8. Examination for muscle tone

   Whether skeletal muscles are unusually rigid or unusually loose, since some drug categories tend to cause each.

9. Check for injection sites and third pulse

   A look for injection marks that can suggest recent use of certain drugs, and the third and final pulse.

10. Subject’s statements and other observations

    Miranda warnings if not already given, then a series of questions about drug use.

11. Analysis and opinions of the evaluator

    Based on the whole evaluation, the DRE decides whether the person is impaired and, if so, which drug category or categories are responsible.

12. Toxicological examination

    A sample of blood, urine or oral fluid is sent to a lab for chemical testing, to provide scientific evidence that supports (or fails to support) the opinion.

Sources: IACP, “12 Step Process”; Beirness & Porath, AAA Foundation (2019). Two features of the sequence frame most DRE cross-examinations. Step 2 means the DRE begins by hearing the arresting officer’s account. Step 12 means the lab result comes last, after the opinion has already been formed. The AAA Foundation review adds a third point: “It is not essential that the toxicology results match the DRE opinion to proceed with charges.”

The seven DRE drug categories and the NC DRE matrix

DREs sort drugs into seven categories: CNS depressants, CNS stimulants, hallucinogens, dissociative anesthetics, narcotic analgesics, inhalants and cannabis. The AAA review notes that these categories reflect shared signs and symptoms and are not necessarily pharmacological classes. The North Carolina DRE matrix lists the signs most consistent with each category. Tap a category to see its profile.

The matrix is a pattern-matching tool. Its own notes say dose, individual reactions and drug interactions produce variations. Combinations, such as alcohol plus a prescription sedative plus caffeine, can mask or cancel one another. That is why the matrix alone cannot prove which drug a person took, much less how impaired he or she was at the time of driving.

The dark room exam and the “normal” ranges DREs use

Pupil size is central to many DRE opinions, and it is estimated rather than measured by an instrument that prints a number. The DRE holds a card with printed circles of known sizes (a pupilometer) next to the eye and picks the closest match in room light, near-total darkness and direct light.

Those ranges are wide and they overlap. A pupil of 5.0 mm in room light is within the normal range; 5.5 mm may be called dilated. Anxiety after an arrest can raise pulse and blood pressure. A cold holding room can lower temperature. Every one of those readings may have an explanation other than drugs, which is why we compare each number on the DRE face sheet with the matrix range and ask what else could explain it.

DRE testimony in North Carolina: Rule 702(a1)(2)

Since 2006, North Carolina’s evidence rules have given certified DREs a specific path to testify as experts on impairment and drug category.

Three limits are written into that text. The DRE testifies about impairment and drug category, not a specific drug, a dose or a blood level. The certification must be current. And it must be issued by DHHS. Rule 702(a) adds the general reliability requirements every expert must meet: testimony based on sufficient facts or data, the product of reliable principles and methods, and, under Rule 702(a)(3), principles and methods “applied … reliably to the facts of the case.”

The impairment the DRE describes connects to the DWI statute itself. G.S. 20-138.1(a)(1) makes it a crime to drive “[w]hile under the influence of an impairing substance,” and G.S. 20-4.01(14a) defines that term to include alcohol, controlled substances under Chapter 90, and “any other drug or psychoactive substance capable of impairing a person’s physical or mental faculties,” or any combination. A separate theory, G.S. 20-138.1(a)(3), applies to “any amount of a Schedule I controlled substance … or its metabolites” in blood or urine, and does not require proof of impairment at all. And under G.S. 20-138.1(b), being legally entitled to use a drug “is not a defense.” See our line-by-line guide to G.S. 20-138.1 and the full Chapter 20 library.

North Carolina cases on DRE testimony

North Carolina’s appellate courts have now drawn the main lines for DRE evidence. More decisions are collected in our NC DWI case law library.

Read together: Fincher says the DRE method does not have to be re-proven in every trial; Moore says the State still has to show the method was applied to this defendant; Lewis shows that only a currently certified DRE may give the opinion, and that it is limited to a category; and Williams shows how courts handle a DRE who never evaluated the driver. Unpublished opinions are not binding precedent in North Carolina, but they show how the Court of Appeals approaches these issues.

U.S. Supreme Court cases that shape a DRE evaluation

How accurate are DRE opinions?

The research is mixed. The 2019 AAA Foundation review concluded that “the literature provides mixed evidence of the accuracy of the DECP.” Laboratory studies give weak support for identifying the specific drug class, while field studies report higher accuracy but may miss or misclassify a substantial share of drug-positive cases.

Even a toxicology “match” has limits. A lab finding that a drug is present does not by itself show it was impairing at the time of driving, because many drugs and metabolites remain detectable after their effects fade. Except for the Schedule I theory, the State must prove the driver was impaired. Our guide to blood and toxicology evidence explains the lab side, and our chain-of-custody case study shows what can go wrong between the draw and the report.

A DRE opinion is a pattern match built on estimates, taken after an arrest, that starts with the arresting officer’s version. Each of those facts is worth testing.Adkins & Purkey

Limits of the DRE evaluation and defense questions

A DRE opinion is only as strong as the evaluation behind it. We request the DRE face sheet and narrative, certification and recertification records, any video of the evaluation, the arresting officer’s report, and the lab report, and then work through the protocol line by line. Our article on how to review DWI evidence covers the broader process.

• Was the DRE’s DHHS certification current on the date of the evaluation?
• Did the DRE personally perform all 12 steps, in order, or rely on records (the Moore problem)?
• How long after the stop did the evaluation start and finish?
• Were three pulse readings taken, and do they fit the claimed category?
• Do the recorded pupil sizes, pulse, blood pressure and temperature actually fall outside the matrix’s normal ranges?
• Do the signs match the category the DRE named, or do some point the other way?
• Were injury, illness, fatigue, diabetes, eye conditions or anxiety considered in step 3?
• Were prescriptions documented accurately, with dose and timing?
• Did the DRE testify to a specific drug instead of a category (the Lewis problem)?
• Did toxicology confirm the same category, and at what level?
• How much of the opinion depends on the arresting officer’s account in step 2?
• What was said in step 10, and were Miranda warnings given first?

What to do if a DRE evaluated you

1. List every medication and supplement you took in the prior few days, with prescriptions, doses and times.
2. Write down medical conditions that affect eyes, balance, pulse or blood pressure, such as diabetes, anxiety disorders, eye conditions or prior head injuries.
3. Note the timeline: the stop, the arrest, the blood draw, and when the DRE started and finished.
4. Write down what you were asked and what you said, especially in step 10. See our guide to Miranda warnings in DWI arrests.
5. Protect your license: the 30-day civil revocation and limited driving privilege rules still apply.
6. Prepare for your consultation with our checklist, and remember that suppression motions in district court generally must be filed before trial under G.S. 20-38.6.

Quiz: how well do you know the DRE rules?

Related guides

Top 10 FAQs: DRE evaluations

General North Carolina legal information as of November 2026, not legal advice for any specific case. Past results and general information do not predict the outcome of any case. Reading this article does not create an attorney-client relationship. Attorney advertising.