What a Drug Recognition Expert Evaluation Actually Tests
The twelve-step DRE protocol is structured, but structure alone does not make every conclusion reliable. A meaningful review asks whether each step was performed, documented, interpreted, and reconciled with the rest of the evidence.
A Drug Recognition Expert evaluation is designed to help a trained officer determine whether a person appears impaired, whether that apparent impairment may be drug-related, and which broad drug category or categories may be involved.
It is not a laboratory test, a medical diagnosis, or an automatic measure of driving impairment. The opinion depends on the quality of the observations, adherence to protocol, timing, alternative explanations, and consistency with toxicology and video evidence.
The twelve steps, in sequence.
The sequence matters because later conclusions are supposed to be grounded in the complete evaluation, not in one test, one symptom, or an assumption carried forward from the arrest.
- STEP 01
Breath alcohol test
The DRE considers whether the breath result is consistent with the degree of impairment the officer believes is present.
- STEP 02
Interview of the arresting officer
The DRE gathers observations, driving facts, statements, test performance, and other information from the initial investigator.
- STEP 03
Preliminary examination and first pulse
The DRE makes initial medical and behavioral observations and asks about health conditions, medications, and drug use.
- STEP 04
Eye examinations
Horizontal gaze nystagmus, vertical gaze nystagmus, and lack of convergence are assessed under prescribed conditions.
- STEP 05
Divided-attention tests
The protocol generally uses modified Romberg balance, walk-and-turn, one-leg stand, and finger-to-nose tests.
- STEP 06
Vital signs and second pulse
Blood pressure, temperature, and pulse are recorded and considered against the overall evaluation.
- STEP 07
Dark-room examinations
Pupil size is assessed under different lighting conditions, along with the nasal and oral cavities.
- STEP 08
Muscle tone
The evaluator checks whether muscle tone appears rigid, normal, or flaccid.
- STEP 09
Injection sites and third pulse
The DRE looks for possible injection evidence and records pulse a third time.
- STEP 10
Statements and other observations
The subject is questioned about drug use, and the evaluator records relevant answers and observations.
- STEP 11
Evaluator's opinion
The DRE forms an opinion about whether impairment is present and, if so, which drug category or categories may be involved.
- STEP 12
Toxicological examination
A blood, urine, or other sample may be analyzed. The laboratory result must be reconciled with the evaluator's opinion and the observed timeline.
A checklist is not the same as a sound opinion.
- Whether the evaluator followed the required sequence and testing conditions
- Whether video supports or contradicts the written report
- Whether medical conditions, fatigue, stress, injury, or prescribed medication offer alternative explanations
- Whether measured signs actually align with the drug category opinion
- Whether the alleged timeline is pharmacologically and factually coherent
- Whether toxicology confirms exposure and whether the result supports impairment at the relevant time
- Whether omissions, copied language, or internal inconsistencies affect the opinion's weight
The complete record matters.
- All body-camera, dash-camera, and booking video
- The complete DRE face sheet, narrative, and matrix
- Arresting-officer and assisting-officer reports
- Breath-test records and instrument documentation
- Laboratory report, underlying data, and chain-of-custody records
- Medical records relevant to symptoms or alternative explanations
- Dispatch audio, CAD logs, photographs, and witness statements
- Training records or manuals relied on by the evaluator
This article provides general educational information, not legal advice or an opinion about any specific case. Standards, procedures, and evidentiary rules vary by jurisdiction.