Houston DWI & What the 12-Step DRE Means

 Posted on June 08, 2026 in DUI/DWI

For most people, the words driving while intoxicated conjure visions of a person inebriated with alcohol behind the wheel of a car. However, there are countless substances capable of intoxication. From prescription drugs to illegal narcotics, these substances present a challenge to law enforcement because all of their training is generally only to determine alcohol impairment.

Unlike the amount of alcohol in the bloodstream, the volume of these substances in the bloodstream cannot be objectively measured because there have not been objectively defined limits for drugs in all persons. The series of tests and observations law enforcement created to use to identify drug intoxication is known as Drug Recognition Expert (DRE) protocol. The DRE protocol is a hocus pocus police tool that has the greatest potential to wrongfully convict a sober and innocent person who is being therapeutically treated by their physician.If you are facing a drug-related DWI charge in 2026, the Houston DWI defense lawyers at our firm are ready to help you challenge this flawed process.

What Is the DRE Protocol?

DRE testing was originally developed in the early 1970s by police officers from the Los Angeles Police Department. By 1979, the DRE protocol was officially adopted by the LAPD. In the early 1980s, DRE testing was adopted by the National Highway Traffic Safety Administration (NHTSA). It has spread in popularity since then, with thousands of officers obtaining DRE training across the country. DRE certifications are currently managed by the International Association of Chiefs of Police.

What Are the 12 Steps of the DRE Protocol?

The DRE is made up of twelve standardized steps designed to detect drivers impaired by substances other than alcohol. However, the reliability of these tests is disputed. In fact, in some jurisdictions, law enforcement is barred from delivering an expert opinion on whether a driver is intoxicated based upon DRE protocol.

Step 1: Breath Alcohol Test

First, the arresting officer will attempt to test a driver's breath alcohol concentration BrAC. It is up to the officer to determine if the signs of intoxication are explained by the BrAC level or if they could potentially be attributed to other substances. The arresting officer may request a DRE evaluation if the intoxication is not attributable to alcohol.

Step 2: Interview of the Arresting Officer

Upon the arrival of a DRE, the investigation begins with a debriefing of the arresting officer. The DRE will discuss with the arresting officer the circumstances of the arrest, including behavior, appearance, and signs of intoxication.

Step 3: Preliminary Examination and First Pulse

The next step involves the DRE taking the pulse of the driver and making preliminary observations. This process includes questioning the driver about any food, alcohol, or drugs they may have ingested recently.The intent of the exercise is to both collect potentially incriminating admissions as well as observe the speech, demeanor, coordination, and attitude of the driver. The pulse reading is the first of three and is also allegedly designed to detect either medical issues or drug use.If the DRE suspects the driver is suffering from a medical issue, it is incumbent on the DRE to seek medical attention for the driver. However, if the DRE believes the driver is under the influence of drugs, the investigation will continue.

Step 4: Eye Examination

The next step involves the DRE examining the eyes of the driver. This step includes a number of tests, including the Horizontal Gaze Nystagmus (HGN) test, the Vertical Gaze Nystagmus (VGN) test, and a lack of ocular convergence.A number of drugs are known to cause HGN, VGN, or a lack of ocular convergence.

Step 5: Divided Attention Psychophysical Tests

The fifth step involves a number of tests, mostly recognized as standard field sobriety tests. These tests include the Romberg Balance, the Walk and Turn, the One Leg Stand, and the Finger to Nose tests. The purpose of these tests is to identify if the driver's motor skills are affected while attempting multiple tasks at once.

Step 6: Vital Signs and Second Pulse

Next, the DRE takes the driver's vital signs and a second pulse reading. Some vital signs can be elevated or lowered by certain narcotics.

Step 7: Dark Room Examinations

The DRE measures the driver's pupil sizes three different times under three separate lighting conditions. Using a tool known as the pupilometer, the DRE measures to determine if the driver's pupils are constricted, dilated, or normal. Some drugs will cause a subject's pupils to constrict, while others will cause them to dilate.

Step 8: Examination for Muscle Tone

The DRE also observes the driver's muscle tone. Certain substances will cause a user's muscles to seize up and become rigid. Other substances can cause a user's muscle structure to become flaccid and loose.

Step 9: Check for Injection Sites and Third Pulse

While taking the driver's pulse a third time, the DRE will also view the driver's visible skin for needle injection sites that could be evidence of recent drug use.

Step 10: Subject's Statements and Other Observations

If the DRE has not done so yet, the officer reads the driver his or her Miranda rights. The DRE then asks the driver additional questions regarding any drug use.

Step 11: Analysis and Opinions of the Evaluator

The DRE next considers all of the previous evaluations during the DRE process and forms an opinion on whether or not the driver is intoxicated and what substances might be involved. The officer's opinion is ultimately subjective, despite the 12-step protocol.

Step 12: Toxicological Examination

After the completion of the investigation, the DRE will request a voluntary blood, urine, or saliva sample to allow for toxicology analysis. Under Texas Transportation Code Section 724.064, the results of a blood or breath test may be admitted as evidence in a DWI trial. However, the mere presence of a substance in the bloodstream does not automatically prove impairment, which is another reason the DRE process remains deeply controversial.

Contact Our Houston DWI Defense Attorneys Today

The most important thing to understand about the results of DRE testing is that the opinion of the expert is just that: a subjective opinion. The DRE consists of a number of subjective observations regarding a driver's vital signs and demeanor, coupled with standard field sobriety testing. Every part of the DRE protocol could lead 10 different DREs to reach 10 different conclusions. It is up to your criminal defense lawyer to show a jury that a DRE opinion is only based on subjective observations and not hard evidence.Attorney Doug Murphy understands that DRE results are based on opinion, not science or facts. As one of only two attorneys board-certified in Texas as an expert in both criminal law and DWI defense, Doug Murphy has the experience necessary to take the facts of your case and craft a trial defense that gives you your best chance at a favorable outcome. In fact, everything the Murphy & McKinney Law Firm, P.C. does is in anticipation of trial. While some attorneys are content to passively wait for a plea offer, Doug Murphy is always looking forward to the next courtroom battle.Contact us at 713-229-8333 to talk to our Houston DWI defense lawyer.