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Published on 8/12/2025, 4:14:00 PM

Drug Recognition Expert (DRE) in Maryland DUI Cases

A Drug Recognition Expert (DRE) is a specially trained officer who follows a standardized 12-step process to evaluate suspected drug-impaired drivers. Their testimony can be influential in DUI drug prosecutions, but the process has inherent limitations that a skilled defense lawyer can exploit.


What is a Drug Recognition Expert?

A Drug Recognition Expert is a law enforcement officer certified through the Drug Evaluation and Classification (DEC) Program to determine whether a person is impaired by drugs, identify the drug category, and document findings in a way intended to meet courtroom standards.

Certification requires completing a multi-phase process that includes classroom instruction, controlled practice, and supervised evaluations on real subjects. Maryland DREs are trained under the same national curriculum developed by the National Highway Traffic Safety Administration (NHTSA) and the International Association of Chiefs of Police (IACP).


The Standardized 12-Step DRE Process

The DRE protocol, as outlined in the official training manual, includes:

  1. Breath alcohol test - ensures low or zero BAC.
  2. Interview of the arresting officer - gathers observations leading to the DRE call-out.
  3. Preliminary examination and pulse - rules out medical emergencies.
  4. Eye examinations - Horizontal and Vertical Gaze Nystagmus, Lack of Convergence.
  5. Divided attention psychophysical tests - Modified Romberg, Finger to Nose, Walk-and-Turn, and One-Leg Stand.
  6. Vital signs check - pulse, blood pressure, body temperature.
  7. Dark room examinations - pupil size under different light levels.
  8. Muscle tone assessment - looking for rigidity or flaccidity.
  9. Injection site inspection - checking common drug use points.
  10. Suspect's statements - questioning about drug use and medical history.
  11. Opinion of Evaluator - selecting one or more of the seven drug categories.
  12. Toxicology - laboratory analysis of blood or urine.

The Seven Drug Categories

DRE training recognizes seven categories, each with distinct physiological and behavioral indicators.

Quick Reference: Seven Drug Categories in the DRE Protocol

Drug Category Common Physical Signs Common Behavioral Signs Example Substances
CNS Depressants Horizontal gaze nystagmus, sluggish pupil reaction, low blood pressure, reduced body temperature Drowsiness, poor coordination, slowed speech Alcohol, benzodiazepines, barbiturates
CNS Stimulants Dilated pupils, elevated pulse and blood pressure, rapid speech Restlessness, anxiety, hyperactivity Cocaine, methamphetamine, Adderall
Hallucinogens Dilated pupils, elevated vitals, muscle tremors Hallucinations, confusion, paranoia LSD, MDMA, psilocybin mushrooms
Dissociative Anesthetics Normal pupil size, increased blood pressure, elevated pulse, rigid muscles Blank stare, repetitive speech, violent or unpredictable behavior PCP, ketamine
Narcotic Analgesics Constricted pupils, low pulse and blood pressure, depressed respiration Euphoria followed by drowsiness, slow reflexes Heroin, oxycodone, fentanyl
Inhalants Variable pupil size, bloodshot eyes, residue around mouth/nose Slurred speech, dizziness, confusion Glue, paint thinner, aerosols
Cannabis Bloodshot eyes, dilated pupils, elevated pulse Relaxed inhibitions, slowed reaction time, altered perception of time Marijuana, THC concentrates, edibles

Medical Conditions That Can Mimic Drug Impairment

The DRE manual itself warns that various medical conditions and injuries can produce signs that look like drug impairment. Examples include:

  • Neurological events such as stroke or traumatic brain injury that can affect balance, speech, and eye movement
  • Inner ear disorders that impact coordination and cause nystagmus
  • Diabetes complications like hypoglycemia or hyperglycemia which may cause confusion, unsteady gait, or slurred speech
  • Seizure disorders or the postictal state that follows a seizure
  • Fatigue or sleep deprivation which can impair divided attention and slow reaction time
  • Head trauma that impacts motor skills and cognitive function
  • Side effects of prescription medications such as antihistamines or blood pressure drugs
  • Mental health conditions like anxiety, depression, or psychosis that can alter demeanor and speech patterns

For defense attorneys, establishing an alternative medical explanation can cast reasonable doubt on a DRE's conclusions.


Key Weak Points in DRE Testimony

From the official training materials, several vulnerabilities stand out:

  • Limited medical expertise - DREs are not medical professionals and their training is not equivalent to clinical diagnosis
  • Failure to follow the full 12-step protocol - skipping steps or altering procedures weakens reliability
  • Subjective interpretation - many signs depend on the officer's perception rather than objective measurements
  • Confirmation bias risk - the DRE is often briefed by the arresting officer before the evaluation, which may influence conclusions
  • Difficulty in combined influence cases - the manual admits that when multiple drugs or a medical condition and drugs are both present, determining cause of impairment is more difficult
  • Certification and recertification requirements - lapses in credentials or insufficient recent evaluations can be grounds for impeachment
  • Error rates in drug category identification - even trained DREs can misclassify impairment category
  • Conflicts between DRE opinion and toxicology results - discrepancies can undermine credibility in court

Why This Matters in Maryland DUI Drug Cases

In Maryland, DUI drug charges under Transportation Section 21-902(c) and 21-902(d) often rely heavily on DRE testimony, especially when toxicology results are pending or inconclusive. If the DRE's conclusions are successfully challenged, it can significantly weaken the prosecution's case.


FAQs

Q: Can a DRE's opinion alone convict me?

A: It is rare, but possible. Prosecutors usually pair it with toxicology, but either can be challenged.

Q: Do I have to agree to a DRE exam?

A: No, but refusal may still result in arrest and may be mentioned in court.

Q: Is the DRE program scientifically validated?

A: The DRE protocol has been studied, but its reliability is still debated in legal and scientific circles.


If you face a DUI drug charge in Maryland, the earlier a lawyer reviews the DRE report, the better your defense options will be. Learn more about Maryland drug DUI defense strategies or how to challenge a DUI stop.