DUI

What is a Drug Recognition Expert?

November 03, 2025 by Yuliya Kelmansky in DUI  
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Driving on Drugs

In most cases, people perceive the phrase driving under the influence (DUI) only as driving under the influence of alcohol and deterioration of mental and motor skills caused by alcohol intoxication. However, a significant proportion of the DUI accused are drug-related.

Along with legal drugs like alcohol and cannabis, illegal drugs such as heroin, meth, cocaine and LSD can result in a DUI.

In California, a person who drives a car under the influence of a drugs – regardless of whether that drug is legal or illegal – can be arrested and prosecuted for driving under the influence. Don’t forget that pharmaceutical drugs and even non-prescription drugs can damage your ability to drive as well.

A police officer has a preliminary alcohol sensor (“PAS”) device. So, when the driver is under the influence of any substances other than alcohol, the policemen can not to determine or gauge by this device the level of drug intoxication of the driver. Thus, when a police officer stops the car and suspects a DUID driver, the officer may demand that the DRE (an expert on the admission of drugs), be sent to the scene of the incident.

Recognizing What You’re High On

A Drug Recognition Expert (DRE) is a law enforcement officer who was trained to detect drug impairment or influence. They do so through a 12-step method, which seeks to identify behavioral and physiological signs of drug influence or impairment.

The 12 steps include:

  1. Breath Alcohol Test is usually performed by a standard-duty officer to rule out alcohol impairment.
  2. Interview by the arresting officer – about the suspect’s demeanor and behaviors and other signs of impairment.
  3. Preliminary Physical Examination – check for pulse, recent medical history or other symptoms and signs of impairment, injury, or a medical condition (skin tone, speech, poor coordination). If the subject’s condition seems to be drug related, the investigation proceeds to next step.
  4. Eye examination – horizontal and vertical gaze nystagmus, eye coordination.
  5. Psychological tests such as Romberg Balance Test, The Walk and Turn Test, The One Leg Stand Test, and the Finger-to-Nose Test for checking for divided attention. These field tests are not mandatory!
  6. Vital Signs – temperature, blood pressure, and pulse.
  7. Darkroom examinations (checking for pupil reactivity to light and signs of drug ingestion.)
  8. Muscle tone examination (e.g. rigid or loose).
  9. Injection site identification & third check pulse – DRE will look at common injection sites for evidence of recent drug use.
  10. Subject’s Statements and Other Observations – If the suspect has not been read Miranda rights, the DRE will do so at this time, followed by a series of questions about drug use.
  11. Summary evaluation – the DRE makes a determination on whether or not the suspect was impaired and what category of drugs may be the cause.
  12. Toxicology analysis – the DRE will request urine, blood, and/or saliva samples for lab analysis, if the DRE determines the suspect was mostly likely impaired by drugs.

Drug Testing Times

Here’s a general idea of the time certain drugs remain in your system, depending on the type of drug test:

Type of drug THC Heroin Cocaine Meth
Time of presence in the blood 4-6 hours after using, with repeated or regular use: over 24 hours. Up to 8 hours A few hours 6 hours
Time of presence in the urine Occasional use: 2-4 days
Weekly: 5-14 days
Daily: 2-6 weeks
5-10 days 5-10 days 5-10 days
Time of presence in 1 cm of hair Traces of taking within a month (low doses undetectable) Traces of taking within a month (low doses undetectable) Traces of taking within a month (low doses undetectable) Traces of taking within a month (low doses undetectable)

We’re Here to Help

If you or a loved one have been arrested and charged with DUI or DUID in Los Angeles, exercise your constitutional rights. Do not sign anything, admit to anything, or agree to anything before you meet and consult with our experienced lawyers.

Need a Criminal Defense Attorney? CALL NOW: 213-932-8922

Yuliya Kelmansky is an Expert Criminal Defense Attorney who has over 10 years of practice defending a variety of criminal cases.

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