A respected workers’ compensation lawyer called Bill Powers this week to ask a favor. A familiar series of questions, fact pattern, and lively conversation followed. While we (Powers Law Firm) don’t handle comp cases and we’re not formally associated with the matter, we do regularly share what we know about the law, science, and technology related to impairment.

It comes with the territory if you build a reputation handling cases involving drunk driving, impairment, and personal injury claims associated with alcohol and wrecks. Plaintiff’s lawyers will call to ask questions about what a lab report means or ask for a reference for an expert witness at trial.

In the most recent inquiry, coworkers apparently say they smelled alcohol on an injured employee and, of course, the insurance adjuster jumped on that, trying to avoid paying the claim. On the positive side of things, hospital records make mention of alcohol. No odor. No red, glassy eyes or slurred speech. No behaviors associated with being impaired, let alone possibly being “drunk.” Blood tests came back with no “EtOH.” No alcohol in the system. And yet, the company insurance adjuster is still fighting the claim.

The frustrated attorney asked, “Bill, what do you think?” If we don’t have a professional conflict (we don’t represent the accused in the criminal DWI charge), we’re always willing to help a fellow courtroom lawyer, provide some background, and when appropriate, agree to serve as co-counsel on certain personal injury claims.

After covering some of the basics, the discussion moved beyond the usual initial pattern of events. Something was off and, having done this a time or thousand, I had a feeling what was going on. Folks were assuming things, not because they’re bad people. The insurance adjuster just flat-out doesn’t understand the science behind what’s going on.

I had questions that, frankly, seemed to surprise the attorney who called.

• What did the employee’s glucose and other metabolic values show?
• Was there evidence of ketosis or diabetic ketoacidosis?
• What did the kidney and liver function testing reveal?
• What was the creatinine level?
• Could an untreated medical condition have produced an odor that coworkers interpreted as alcohol?
• Had anyone asked the laboratory or medical questions needed to test that possibility?

The question was no longer simply who smelled alcohol. It became what potentially produced the odor, what the objective evidence showed, what science could reliably prove, and whether that “odor of alcohol” was actually evidence of something else entirely.

That kind of problem regularly appears in personal injury and wrongful death claims involving suspected impaired driving. To put it mildly, drunk driving accident cases tend to be pretty complicated and can be confusing if you don’t understand the science behind what’s going on. That’s yet another reason we think it’s smart to talk to someone who has a fair amount of experience handling such cases.

A laboratory number may appear definitive until you take a look at things like the collection time, testing methods and the lab report units, standard treatment protocols, and the all-too-regular incorrect assumptions people make. An officer may describe impairment while the body-camera recording shows something quite different. A drug or prescribed medication may be present without proving impairment at the time of the collision due to functional tolerance. An unknown and/or undiagnosed medical condition can produce certain clues that might make a witness mistakenly infer someone was drunk due to alcohol or drug consumption or both.

Sometimes evidence that changes a case is not always precisely labeled as “impairment.” Looking at medical records with an experienced eye can help. We think it helps to carefully consider the background of how a specimen was collected, stored, and tested. We also review records for medication administration, blood collection times, metabolic panels, IV fluid records, and tox (toxicology) notes. And if law enforcement is involved, it’s not unusual to peruse officer training materials, their level of experience, certifications such as ARIDE or DRE-level background, and video evidence that very well might not fit the written narrative.

I’ve spent more than three decades examining those types of evidence in North Carolina impaired-driving cases. It’s natural I’d rely on that experience if someone calls, needing help with an accident or wrongful death claim.

Indeed, just this past Friday (August 28, 2026) I was honored to speak to some Charlotte-Mecklenburg police recruits as a guest of the Charlotte-Mecklenburg Police Department’s DWI Task Force. If I understood them correctly, they are about 1/2 way through their training and hope to finish up BLT by mid-November. My segment of the SFST block addresses courtroom protocols and procedures associated with driving while impaired cases.

I also enjoy teaching and chairing continuing legal education programs for lawyers, courses for sworn law-enforcement officers, programs with prosecutors, and presentations for judges. If I’m going to attack a 702 Expert Opinion, I should be willing to share my knowledge of impaired-driving law, science, testing, and courtroom procedure across professional lines.

That is one reason I think other lawyers call me with questions.

Sometimes the answer is found in a single medical record or laboratory report. Sometimes the lawyer needs help identifying a scientific witness or preparing an examination. And, in selected cases, Powers Law Firm is available to serve as co-counsel and handle the impairment evidence within a larger personal injury or wrongful death claim.

Medical Conditions That May Resemble Alcohol or Drug Impairment

Medical records should not be treated as a stack of documents showing only injuries and treatment. They may contain evidence that explains the defendant’s appearance, behavior, speech, coordination, memory, laboratory results, or perceived odor.

Diabetic ketoacidosis can produce acetone or fruity-smelling breath that a lay witness may associate with alcohol. Hypoglycemia can produce confusion, weakness, sweating, unusual behavior, speech problems, or loss of coordination. Neurological events, head injuries, infections, kidney disease, liver disease, medication effects, and other conditions may also affect behavior or laboratory findings.

The existence of a possible medical explanation does not establish that it caused the observed conduct. It identifies a question that may be tested through the records.

Depending upon the facts, the review may include glucose, ketones, bicarbonate, anion gap, creatinine, blood urea nitrogen, liver enzymes, medication history, vital signs, neurological findings, intravenous fluids, and physician or nursing observations. The significance of those findings may require evaluation by a physician or another witness working in the appropriate medical discipline.

The chronology also matters. A laboratory value collected after intravenous fluids, medication, surgery, blood loss, or other treatment may not describe the patient’s condition when driving. A chart entry copied forward from another note may not represent an independent observation. A medical notation may reflect information provided by law enforcement rather than a conclusion reached by the treating clinician.

The purpose of examining those records is not to manufacture doubt. It is to determine whether the reported explanation is consistent with the objective medical evidence.

Sometimes the records confirm alcohol or drug impairment. Sometimes they identify a competing explanation. Sometimes they reveal that the available evidence cannot answer the question with the confidence someone initially assigned to it.

Pharmacokinetics | Blood Alcohol Evidence in a Civil Claim

Pharmacokinetics describes what happens to a substance as the body absorbs, distributes, metabolizes, and eliminates it. The process is commonly abbreviated ADME. The National Library of Medicine identifies those four stages as the foundation of pharmacokinetics.

In an alcohol-related claim, pharmacokinetic questions may include when drinking began and ended, whether alcohol was still being absorbed, how food affected absorption, when the specimen was collected, and what assumptions would be required to estimate an earlier concentration.

The answers may depend on facts that no laboratory instrument can supply.

A retrograde extrapolation attempts to estimate an earlier alcohol concentration from a later result. The calculation may require assumptions about when absorption was completed and which elimination rate should apply. If the drinking history is incomplete, inconsistent, or disputed, the calculation may produce a precise number without a reliable factual foundation.

Mathematics can show what follows from an assumption. It cannot establish that the assumption was true.

The reverse problem can also occur. A low or negative result may appear less meaningful until the delay between the collision and specimen collection is considered. Alcohol may have been eliminated during that interval. The importance of the result depends upon the collection time, available drinking history, testing method, and other evidence.

Hospital alcohol testing presents additional questions. Serum and plasma values are not numerically interchangeable with whole-blood alcohol concentrations. The laboratory method may differ from the method used in a forensic toxicology laboratory. A lawyer should not apply an assumed conversion without understanding the specimen and analytical process.

Drug testing requires similar care. A preliminary immunoassay screen may identify a class of substances but may not provide the specificity of confirmatory testing. The presence of a metabolite may establish prior exposure without establishing active impairment. Therapeutic, toxic, and impairing concentrations do not always fall into simple categories that apply equally to every patient.

Our review may begin by placing the collision, emergency response, officer observations, roadside testing, arrest, breath testing, blood collection, hospital treatment, and laboratory analysis on a single timeline.

That timeline may expose an unexplained delay, a result obtained during absorption, a disputed last-drink time, an unsupported elimination rate, or a medical intervention that must be considered before interpreting a hospital result.

It may also reveal that the scientific evidence supports impairment more strongly than the original police narrative suggested.

The analysis should follow the data, even when the data leads somewhere unexpected.

Scientific Witnesses Under North Carolina Rule 702

Scientific witness selection per Daubert ordinarily begins with the question the case requires the witness to answer.

A physician may diagnose and explain a medical condition but have little basis to interpret forensic alcohol testing. A laboratory analyst may describe how a specimen was tested but lack the foundation to diagnose a metabolic disorder. A toxicologist may interpret concentration and metabolism but have no role in reconstructing the movement of the vehicles.

North Carolina Rule of Evidence 702 governs scientific and technical opinion testimony. It addresses sufficient facts or data, reliable principles and methods, and the application of those methods to the facts. The rule also contains provisions addressing Horizontal Gaze Nystagmus and Drug Recognition Evaluator testimony.

Not every claim requires every discipline in the table. The scientific question should determine the witness, rather than selecting a witness first and then searching for an opinion.

Bill’s role may include defining that question, identifying the appropriate discipline, developing the records the witness needs, helping prepare direct examination, and anticipating the subjects opposing counsel may address on cross-examination.

Cross-Examination in a Drunk Driving Personal Injury Case

Impaired-driving cases regularly involve both direct and cross examination of three different categories of witnesses.

The first is law enforcement. An officer may have extensive road experience but still forget to give a specific NHTSA instruction, vary from training, and later come to a conclusion regarding impairment, or nonimpairment, that is either contrary to the BAC or inconsistent with what’s actually going on.

Plaintiff’s lawyers may find it important to carefully review the officer’s report and testimony, together with the BWC (Body Worn Camera) video evidence, lab report, medical record, and on-scene witness statements.

The second potential evidentiary category involves an opposing scientific witness. The “other side’s” 702 Expert. Cross-examination in those instances tends to focus on the bases for opinions and the related assumptions in formulating the opinion.

Questioning the foundation of an expert opinion is not necessary an attack on science. Quite the contrary, challening a contrary expert opinion regularly focuses on whether the scientific literature and best practices support the conclusions drawn.

The third category of evidence may involve the defendant, the party responsible for the accident, resulting injury, and, in some tragic circumstances, the wrongful death of another. That may involve calling into question the timeline of events, drinking patterns, what illegal drugs or medications were taken, what happened after the accident, and what was said to officers or EMS or medical personnel during treatment.

Receipts, text messages, photographs, and video can all prove important to that endeavor.

Liability & Damages | Impaired-Driving Injury Claim

Scientific evidence can affect how much the claim is worth. Indeed, folks injured in an accident often ask, “How much is my case worth?” While understandable, the answer is a bit nuanced. From the plaintiff’s lawyer’s perspective, not only are we looking for the amount of damages; part of the job is searching for legal liability.

Put simply, is more than one person or party responsible? Is there more than one insurance policy available to make the injury party “whole,” to restore them, financially, as close to where they were one minute before the wreck? That consideration may result in considering whether there are legitimate claim against a bar, restaurant, employer, vehicle owner, or another legally responsible party. That can also involve identify uninsured or underinsured motorist coverage issues. Particularly when a wreck involves allegations of drunk driving, there may be a possible claim for punitive damages.

The availability of a claim against another party obviously depends upon the facts and NC accident law, including potential defenses such as contributory negligence. Proof that the “at fault” driver was impaired does not automatically mean there is legal liability against every business, employer, social host, or vehicle owner connected to the defendant or the wreck.

Punitive damages are not automatic in a drunk driving lawsuit. N.C.G.S. § 1D-15 requires compensatory liability and clear and convincing proof of fraud, malice, or willful or wanton conduct related to the injury.

N.C.G.S. § 1D-26 provides that the ordinary punitive-damages cap does not apply to a claim arising from the defendant’s operation of a motor vehicle when that operation would give rise to an impaired-driving offense identified in the statute.

The difference between suspected drinking and provable impaired driving may therefore affect more than the basic negligence claim. The evidence may affect available claims, responsible parties, settlement analysis, admissible testimony, and what a jury may lawfully consider.

No settlement or verdict can restore a lost life or erase a permanent injury. Careful scientific work can help the injured client or family pursue the compensation and accountability North Carolina law permits.

Our pages on North Carolina drunk driving accident claims, dram shop and social host liability, and North Carolina wrongful death claims provide additional information about those civil claims.

North Carolina Impaired-Driving Co-Counsel Beyond Charlotte

Older readers may remember Paladin and the television series Have Gun, Will Travel.

The Powers Law Firm version involves considerably less gunplay.

Have science, will travel.

A serious impaired-driving injury or wrongful death claim may require assistance outside Charlotte and Mecklenburg County. Geography does not decide whether a consultation makes sense.

The nature of the scientific question, the seriousness of the loss, the procedural posture, the available evidence, and the role requested by existing counsel all inform whether Powers Law Firm may be available to help.

Free Consultations for North Carolina Lawyers and Injury Victims

If you are a North Carolina plaintiff’s lawyer and something about the impairment evidence does not make sense, call Bill Powers.

You do not need to identify the scientific theory before the conversation. The point of the consultation may be to determine what question the evidence is presenting.

The initial consultation is free. The discussion may address a laboratory result, medical record, testing procedure, timeline, scientific witness, deposition, or potential co-counsel relationship. A brief review may answer the question. A more complicated claim may require additional records or assistance from someone working in a particular scientific or medical discipline.

In selected cases, Bill may be available to serve as co-counsel and handle the impairment evidence with existing counsel.

If you or your family suffered serious harm because of a suspected impaired driver, Powers Law Firm may be available to help. The firm represents plaintiffs in serious personal injury and wrongful death matters and evaluates the legal, medical, insurance, and scientific evidence associated with the collision.

Lawyers, injured clients, and families may call or text Powers Law Firm at 704-342-4357.

Sometimes the obvious answer answers the question. Sometimes the evidence is telling you there is something more.

Who is Bill Powers? | Impaired-Driving Science in North Carolina

Bill Powers has practiced law in North Carolina since 1992. He is Board Certified in Criminal Law by the National Board of Trial Advocacy and the longtime author of the North Carolina DWI Quick Reference Guide. He served as President of the North Carolina Advocates for Justice and received the North Carolina State Bar’s John B. McMillan Distinguished Service Award.

Bill currently serves as the North Carolina Advocates for Justice representative on the Governor’s DWI Task Force. He has served in that capacity during the administrations of Governor Pat McCrory, Governor Roy Cooper, and Governor Josh Stein.

His work with the Task Force involves policy discussions about impaired-driving metrics, drunk driving related fatalities and accidents, law enforcement, scientific testing and the related technology, proposed legislation, and the NC judicial system and courtroom practice. It also provides an opportunity to present the perspective of the defense bar during statewide discussions of North Carolina impaired-driving law.

Many lawyers know Bill through his DWI defense work. Fewer may realize that Powers Law Firm also represents injured plaintiffs and families in civil claims against impaired drivers and other legally responsible parties.

The scientific method does not change because the client’s seat in the courtroom is across the aisle. A blood result must still be interpreted correctly. A retrograde calculation still depends on its underlying assumptions. An officer’s conclusion must still be compared with the recording and the officer’s training. A medical condition may still explain conduct or an odor that someone attributed to alcohol. A toxicology opinion still requires reliable data and a defensible methodology.

Years spent challenging impaired-driving evidence can provide a useful perspective when that evidence supports an injured plaintiff. You know which records to request, which assumptions require testing, where laboratory terminology may create confusion, and how opposing counsel may attempt to limit or explain the scientific proof.

Our involvement can be tailored to the needs of the lawyer and the case. Assistance may include reviewing medical or toxicology records, identifying missing evidence, developing a testing timeline, preparing for depositions, helping select an appropriate scientific witness, or preparing direct and cross-examinations.

In selected cases, Bill at Powers Law Firm may serve as co-counsel through discovery, mediation, or trial while the referring lawyer continues to manage the larger civil claim. Call now to schedule a confidential consultation: 704-342-4357. Prior to discussing the matter, the firm will conduct a conflicts check to confirm availability for representation.