How Are Drug Recognition Experts Involved in DUI Cases?

If you get pulled over for a DUI, what happens if a DRE asks to give you a drug influence evaluation? What happens if you refuse?

By , Attorney · George Mason University Law School

In a drunk driving case, the prosecution can typically prove that someone is guilty either by showing that their BAC was over the limit or that their driving was impaired by alcohol. In a drugged driving case, on the other hand, prosecutors often have to show that the driver was impaired by whatever substance they took. So, when police suspect a driver of drugged driving, they often need detailed evidence showing how and the extent to which the driver was impaired.

That's where drug recognition experts (DREs) come in. A police officer who suspects someone of DUI but doesn't observe any signs of alcohol use might request a drug recognition expert—also called a "drug recognition evaluator" or "drug recognition examiner"—to help determine if the driver is under the influence of drugs.

What Is a Drug Recognition Expert? What Do DREs Do?

A DRE is a police officer who does special training to get certified to conduct drug influence evaluations (DIEs). DREs use DIEs to determine both whether a driver is under the influence of drugs and which category of drug is affecting the driver.

What Is a Drug Influence Evaluation?

A DIE is a 12-step process. Drug recognition experts use it to determine whether a DUI suspect is impaired by drugs and what kinds of drugs are involved.

The DIE is designed to detect seven categories of drugs. Each category affects a person's central nervous system differently.

Some police departments and courts might use another name for drug influence evaluations, such as "drug recognition examination" or "drug recognition evaluation."

Some of the 12 steps in a drug influence evaluation might happen at the scene, but the entire DIE often is conducted at the police station or jail, after the police arrest the driver. The 12 steps are:

  1. A breath alcohol test to determine whether alcohol is involved.
  2. An interview of the arresting officer.
  3. A preliminary examination to determine whether the suspect has an injury or other health issues. (This step includes questions about health, questions about drug use, observing the suspect's behavior, and taking the suspect's pulse.)
  4. An eye examination for signs of impairment.
  5. Four field sobriety tests (the modified Romberg balance, the walk and turn, the one-leg stand, and the finger-to-nose test).
  6. Taking the suspect's blood pressure, temperature, and pulse.
  7. A dark-room exam to observe the suspect's pupil sizes under three different lighting conditions.
  8. An examination of the suspect's muscle tone.
  9. An examination for needle injection sites and taking the suspect's pulse a third time.
  10. Further questioning the suspect about drug use.
  11. Determining, based on the above steps, whether the suspect is impaired and, if so, by what categories of drugs.
  12. Chemical testing of the suspect's blood or urine.

What Training Does a DRE Have?

To be a DRE, a police officer needs to get certified by the Drug Evaluation and Classification Program (DECP). The International Association of Chiefs of Police runs the DECP with support from the National Highway Traffic Safety Administration.

A police officer must complete a Standardized Field Sobriety Testing (SFST) course before beginning the DECP. The DECP itself has three phases:

  1. the 16-hour DRE pre-school, which includes an overview of the DIE process
  2. the 56-hour DRE school, and
  3. completion of 12 drug evaluations with a minimum 75% toxicological corroboration rate and completion of a final exam.

Step 2, the 56-hour DRE school, is the most intensive part of the certification process. It involves seven days of instruction on the DIE process, including:

  • identifying drug categories and combinations
  • taking vital signs, and
  • preparing a case for court.

A DRE candidate must pass a written exam before moving to the third phase of the DECP. After completing the third phase, the candidate gets the DRE certification.

DREs also need to be recertified every two years. The recertification process includes:

  • performing at least four acceptable DIEs since the DRE's last certification or recertification
  • a certified DRE instructor witnessing one of those DIEs, and
  • eight hours of recertification training.

Under the DECP, only police officers with active DRE certifications may conduct DIEs on suspected drunk drivers.

Can I Refuse a Drug Influence Evaluation?

In almost every state, a driver can refuse the DIE without penalty. But Connecticut, for one, is an exception. There, a person who is arrested for a DUI must comply with the "nontestimonial" portions of the DIE or face a mandatory license suspension. (Conn. Gen. Stat. § 14-227b (2023.) In other words, arrested drivers must do all of the steps except for the questioning in steps 3 and 10. (That's because a person under arrest has a constitutional right to remain silent and generally can't be punished for exercising that right.)

Regardless of what state law says about cooperating with DIEs, a state's implied consent law might require you to cooperate with some steps that happen to be part of the DIE—most notably, the chemical test.

In general, steps 2 through 10 are voluntary in most states, meaning a driver can refuse them without punishment. (In reality, people often comply because they feel intimidated by the police and believe that agreeing to a DIE is their best option.) But chemical testing of blood, breath, or urine often is required, and a person who refuses can face serious penalties, such as a year-long license suspension.

Are Drug Influence Evaluations Reliable? Can I Challenge a DIE?

The DIE has a lot of critics, including defense attorneys and civil rights organizations. They make several arguments against its reliability, including these claims:

  • DREs have limited training and education compared to toxicologists (scientists who study chemicals and other substances).
  • DIEs require medical diagnoses, but DREs have no medical training.
  • The DIE is biased because law enforcement agencies created it to help prove DUI cases.
  • Studies show that DIEs have high rates of misidentification of drugs.
  • The DIE isn't a reliable tool for determining whether a person's ability to drive has been impaired.
  • DREs are biased—intentionally or not—and begin the evaluation with their minds made up.

Prosecutors and law enforcement respond with the position that the DIE is an accurate tool and that studies support its reliability.

Despite the above critiques, judges generally will allow a DRE to testify that a DIE showed a defendant was impaired by a drug. Though, some courts have rejected the scientific basis of the DIE. These courts have prevented DREs from giving testimony about the results of the DIE and whether the driver was impaired by a drug.

If a judge allows a DRE to testify in court, the defense can try to attack the DRE's training, the results of the DIE, or both. However, doing so can be difficult without a thorough understanding of the DIE process or drugged driving investigations. The defense might need to use an expert, such as a toxicologist, to challenge the DRE's opinions.

Attacking a DRE's testimony can be complicated, which is one of many reasons it's normally a good idea to have a lawyer for a DUI case.

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