How Expert Witnesses Are Used in a Texas 18-Wheeler Accident Case

An expert witness is someone a court allows to give an opinion because the subject needs specialized knowledge, such as how a crash unfolded, what a trucking company was required to do, or what an injury will mean over time. Under Texas Rule of Evidence 702 the person must be qualified and must help the jury understand the evidence, and the trial judge decides whether the opinion is reliable enough to be heard.

What does an expert witness do in a Texas truck accident case?

An expert explains a technical subject and gives an opinion about it, which an ordinary witness may not do. In a truck case the subjects are often technical: stopping distances, federal safety rules, electronic records, injuries. Rule 702 allows the testimony when it will help the jury decide a fact in issue.

The rule reads, in full: “A witness who is qualified as an expert by knowledge, skill, experience, training, or education may testify in the form of an opinion or otherwise if the expert’s scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue” (the Texas Rules of Evidence as amended through July 2, 2026). Rule 703 lets an expert base an opinion on facts or data the expert has been made aware of, reviewed or personally observed, and Rule 704 says an opinion is not objectionable just because it embraces an ultimate issue.

Truck cases lean on experts because the evidence is specialized from the start: a commercial truck answers to federal rules and to a company with records of its own, which is part of why an 18-wheeler claim is built differently from a car claim. The firm’s Houston truck accident page describes how these claims are handled, and the article on a truck lawyer’s work from first call to resolution places expert work in the larger sequence.

How does a Texas judge decide whether an expert may testify?

The judge acts as a gatekeeper. In E.I. du Pont de Nemours & Co. v. Robinson (Tex. 1995), the Texas Supreme Court held that Rule 702 requires expert testimony to be relevant and reliable, and that once the opposing party objects, the party offering the testimony bears the burden of showing it is admissible.

The Robinson opinion (923 S.W.2d 549, No. 94-0843, June 15, 1995) arose from a claim that a contaminated fungicide damaged a pecan orchard, and the court affirmed the exclusion of the plaintiffs’ only causation expert. It listed factors a trial court may weigh, including whether the theory can be tested, how far the technique depends on the expert’s subjective interpretation, peer review, the rate of error, general acceptance and non-judicial uses, and stressed that the list is “non-exclusive.”

That framework came from a scientific-evidence dispute. The practical lesson is that an opinion has to rest on a method that can be explained and examined; credentials qualify the witness, and the reliability of the reasoning is a separate question for the judge.

What kinds of experts are used in an 18-wheeler case?

The usual categories are crash reconstruction, trucking safety and federal regulations, electronic data, medical opinion on injury and future care, and economic analysis of losses. Which are needed depends on the crash and the injuries; a case may use two of them or all five.

The other side may name experts too, so one crash can produce two reconstructions that disagree. The judge’s gatekeeping role and the jury’s weighing of the evidence apply to both.

What does a trucking-safety expert look at?

A trucking-safety expert compares what the company and driver did against the federal safety rules. That means the carrier’s duty to require drivers to follow the rules, its inspection and maintenance system, and its hours-of-service records. The expert explains the standard to the jury and shows where the records meet it or fall short.

The federal rules put duties on the company, not just the driver. Under 49 C.F.R. § 390.11, whenever part 325 or the motor carrier safety subchapter prescribes a duty or prohibition for a driver, “it shall be the duty of the motor carrier to require observance of such duty or prohibition.” Section 396.3 requires every motor carrier to “systematically inspect, repair, and maintain” the vehicles subject to its control. A safety expert reads those records and explains what a compliant system looks like.

Hours records are a second source. The carrier must also keep each driver’s duty-status records and supporting paperwork (49 C.F.R. § 395.8). How long each kind of record must be kept is set out in the post on evidence that decides a truck claim, and the limits themselves in the explanation of the hours-of-service limits. Who answers for what is a separate question, taken up in the liability article.

A Houston example: ABC13’s July 1, 2026 story on a fatal I-10 inbound crash near Eldridge, where an 18-wheeler struck a car and two people died, tied the truck to a small Richmond carrier whose national safety records listed 10 trucks and one other crash in the prior 24 months (ABC13 Houston). It assigned no fault; it does show that public carrier records exist for an expert to start from.

How does a reconstruction expert use the truck’s recorded data?

A reconstruction expert tests a theory of the crash against physical evidence and any records the truck produced. Electronic logging devices must automatically record date, time, location, engine hours and vehicle miles, which can place the truck and check a driver’s account.

The data a logging device must capture is listed in 49 C.F.R. § 395.26, and what that data can and cannot show is covered in the evidence post. While the vehicle is moving the device also logs an entry at least hourly, which makes the record coarse rather than a second-by-second film of a crash. Whether a particular truck holds any other recorded data is a fact to establish for that vehicle.

Physical evidence such as the final resting positions, damage and roadway marks is combined with those records to test competing accounts. Articles on a truck that fails to stop, a tire failure on the highway and a distracted truck driver each show different facts a reconstruction has to account for. Because records can be discarded, an early step is often a written request to keep the truck and its data, covered in the steps listed in what to do after a truck wreck.

Do medical bills in a truck case need an expert or an affidavit?

Texas lets a provider or records custodian prove that a charge was reasonable and a service necessary by sworn affidavit, if it is served on time and not controverted. The affidavit cannot prove causation. Whether the crash caused an injury, or aggravated an old one, calls for medical opinion.

Under Civil Practice and Remedies Code § 18.001, an uncontested affidavit of that kind is sufficient evidence for a fact-finder to find the charge reasonable or the service necessary, and subsection (b) adds that it does not support a finding on causation. It must come from the person who provided the service or the person in charge of the billing records, include an itemized statement, and, in the usual case, be served by the earlier of 90 days after the defendant files an answer or the deadline to designate experts set by court order or the civil procedure rules. A party who disputes it serves a counteraffidavit from a qualified person, which also cannot be used on causation.

Two practical points follow. Recovery of medical expenses is further limited by § 41.0105 to what was actually paid or incurred for the claimant, a limit that interacts with the types of damages in an injury claim. And when a crash aggravated an earlier condition, a physician’s causation opinion carries the case, the subject of proving aggravation of a pre-existing condition. A driver’s own health can matter on the other side of the ledger, as in the piece on a driver’s own health history.

How can the other side challenge an expert witness?

It can ask the judge to exclude the opinion, ask to question the expert about the facts and data underneath it before the jury hears the opinion, and cross-examine afterwards. Rule 705 supplies these tools and makes an opinion inadmissible when the underlying facts or data are not a sufficient basis for it.

Under Rule 705(a) an expert may give an opinion and reasons without first testifying to the underlying facts, but “may be required to disclose those facts or data on cross-examination.” Under 705(b), before the opinion is stated, an adverse party in a civil case may be permitted to examine the expert about that basis outside the jury’s hearing. Paragraph (c) ends a weak opinion: it is “inadmissible if the underlying facts or data do not provide a sufficient basis.”

A defense expert’s opinion faces the same screening. Insurer habits are covered in mistakes to avoid after a Houston truck crash, and how a carrier’s coverage shapes a claim is in insurance after an 18-wheeler crash.

How is an expert different from an eyewitness or the investigating officer?

An eyewitness describes what the person perceived. An expert applies specialized knowledge to facts, often facts the expert did not see. Under Rule 701 a witness who is not an expert may give an opinion only if it is rationally based on perception and helpful to understanding the testimony or a fact in issue.

A driver who saw the truck drift can say so; whether its brakes were out of adjustment is a question for someone trained to answer it. The article on why eyewitnesses matter in a Houston crash covers what ordinary witnesses add. In the ABC13 report, the Houston Police Department described how the 18-wheeler struck the car and Sheriff Ed Gonzalez said the investigation was continuing; those are early accounts, and a technical point is usually explained to a jury by a witness whose job it is to do that. Where impairment is the issue the proof differs again; see proving drug use by truck drivers, and for the data on why trucks crash see common causes of Houston truck accidents and hiring a lawyer for an interstate carrier case.

In Houston, the police officer who reconstructs a crash usually belongs to a criminal investigation: the Houston Police Department’s Vehicular Crimes Division says its Crash Reconstruction unit “provides technical expertise for fatal crashes and all other vehicular crashes with a criminal nexus” (HPD Vehicular Crimes Division). An expert retained for a civil claim is a different witness with a different assignment, and the officer’s work is one more record such an expert may review.

If you were hurt in a Houston-area truck crash, the records worth asking about and the kinds of experts a case would involve depend on what the crash involved. The injury practice page and the truck settlement page describe the work; the timeline article shows how long cases run, and the notes on sharing medical records with an adjuster are worth reading before any call. A particular truck case can be raised on the contact page, and what is said there is covered by the rules in the piece on attorney-client privilege; the value of a Houston claim is a separate question. Where an expert would start is covered in the article on evidence in an 18-wheeler claim, and driver testing is the subject of the piece on proving drug use by truck drivers. When a carrier’s conduct looks worse than careless, the gross negligence article explains the separate test and higher burden of proof that apply.

About the authors

Sam A. Maida, Jr.

Owner and Managing Attorney

Sam A. Maida, Jr. has represented injured Texans in the greater Houston area since the firm opened in 1993.

Texas Bar No. 00787950

State Bar of TexasAvvoMartindale-HubbellLawLinkThatCarHitMeLinkedIn

Bernard G. Johnson III

Litigation Managing Attorney

Bernard G. Johnson III is a board certified trial lawyer licensed in Texas since 1996 and a graduate of South Texas College of Law.

Texas Bar No. 00796832
Admitted to practice in the U.S. District Court for the Western District of Texas (2004)

State Bar of TexasSuper LawyersFindLaw