The Accident Reconstruction Expert Witness: Referrals for Plaintiff and Defense Attorneys

accident reconstruction expert witnessCo-authored with Lauren Solari

The outcome of many personal injury cases hinge upon the testimony of an accident reconstruction expert witness. Such experts also play an important role in criminal matters, products liability, and insurance disputes.

Who Is An Accident Reconstruction Expert Witness?

Accident reconstruction experts obtain measurements, create models, and re-create accidents. They discuss the people, vehicles, roadways, objects, and entities involved, provide testimony about the timeline of events, and opine on contributing factors rendering a product defective. Even in situations where the accident-site has been repaired or altered, an accident reconstruction expert witness can contribute important testimony by analyzing a report or a deposition and ascertaining its merit and reliability.

An accident reconstruction expert witness provides critical testimony about the timeline of events and the factors contributing to an accident. Accident reconstruction experts obtain road and debris measurements, collect information about the nature of the accident victims’ injuries, and investigate factors such as speed and breaking, visual impairments, and weather conditions. They perform experiments and re-create accidents and discuss the people, vehicles, roadways, objects, and entities involved in an accident.

Certain accident reconstruction experts specialize in forensic engineering, focusing on the individual components of a motor vehicle, consumer product or piece of equipment. Generally, an accident reconstruction expert witness is a computer software engineer specializing in accident reconstruction. Or they may be an experienced policeman or other governmental officer who has investigated hundreds if not thousands of accidents.

Issues Benefiting From The Testimony Of An Accident Reconstruction Expert Witness

An accident reconstruction expert witness explains technical terminology and industry standards, assisting the finder of fact determining liability and damages. Cases in which attorneys choose to call an accident reconstruction expert witness involve issues such as:

  • Air Bags
  • Automatic Traffic Signal
  • Brake Systems
  • Collision Analysis
  • Collision Speed
  • Crash Worthiness
  • Injury Analysis
  • Seatbelts
  • Skid Marks
  • Speed Determinations
  • Stability Control
  • Steering Angles
  • Suspension Systems
  • Vehicle Failure


Depending on the complexity of the case details, an accident reconstruction expert may choose to create an animation depicting the accident.

Experts create videos by constructing a model scale of the accident scene based on physical evidence and photographs of the wreckage. They demonstrate what the aftermath of the crash would look like based on the plaintiff and defendant’s respective theory. Such visual aids may enable the finder of fact to better comprehend the context and the sequence of events surrounding an accident.

In hiring an expert witness, it is best to select an expert with the specific subject matter expertise on the issue at hand.  In Lopez-Juarez v. Kelly, the plaintiff lost her wrongful death action against a tour bus operator in part for presenting a “police officer [who] was not qualified to testify as an expert witness regarding accident reconstruction.” 348 S.W.3d 10 (Tex. App. 2011). As the recent case illustrates, it is critical to hire a qualified and reliable accident reconstruction expert .

Cases Involving An Accident Reconstruction Expert Witness

accident reconstruction expert witnessPlane Crashes

In providing testimony in an aviation lawsuit following an airplane accident, an accident reconstruction expert typically reviews and analyzes flight data from the cockpit voice recorder (CVR) or the digital flight data recorder.

According to the American Bar, before an expert witness may obtain and analyze the CVR, a party must demonstrate not only relevance but also that the written transcript of the CVR is not adequate. The CVR records all the audio within the cockpit, including any and all conversation between the cockpit, crew, and air traffic controllers. Yet, this is not a high barrier to overcome. The party can argue that the “expert needs to listen to the CVR in order to ‘recreate exactly what happened in the cockpit.’”

Based on the written transcript and audible recordings, an accident reconstruction expert may opine on the pilot’s state of mind and situational awareness. Further, this evidence may enable the expert to determine whether human error or product malfunction was the cause-in-fact of the accident.

Case Example: Desrosiers v. Flight International, 156 F. 3d 952 (9th Cir. 1998)

Following a plane crash in which one service member was seriously injured and another was killed, a trial was held to determine liability during which the plaintiff’s accident reconstruction expert witness provided testimony that was “reliable, relevant, and helpful to the trier of fact.”

However, the defendant attempted to bar the testimony from evidence.

In upholding the introduction of the plaintiff’s plane crash reconstruction expert, the court noted the expert’s “extensive experience with instrument analysis and electronic equipment” and the fact that his “methodology included extensive review of maintenance records, wreckage, depositions, service manuals, textbooks, and the radar tape.”. Moreover, the court emphasized that given the magnitude of the destruction that occurred in the crash, “the circumstantial evidence [the accident reconstruction expert witness] employed was the best information available to reconstruct the accident.”

Products Liability

In a products liability case, the plaintiff has the burden of proving: (1) the defective and unreasonably dangerous condition of the defendant’s product; and (2) a causal connection between the defendant’s product and the plaintiff’s injuries or damages.  Such a case can be brought under a strict liability theory, negligence theory, breach of warranty theory, or all three.

The existence of a product’s defective condition can be established through an expert’s opinion formed after an examination of the product at issue.  Accordingly, the testimony of an accident reconstruction expert witness can be tremendously persuasive in resolving whether a product’s defective design was the cause of the accident that resulted in the plaintiff’s injuries or whether the plaintiff’s actions caused the accident.

In the seminal case Barris v. Bob’s Drag Chutes & Safety Equipment, Inc., the plaintiff’s accident reconstruction expert provided critical testimony in a products liability case regarding a racecar driver who was fatally injured during a race where his car flipped several times and his shoulder harness broke.  In a lawsuit against the manufacturer and retailer of the involved shoulder harness, the plaintiff’s expert testified that the harness failed to restrain the driver under normal use.

The plaintiff’s accident reconstruction expert witness opined that inferior stitching on the harness caused the product to fail.  The expert arrived at this conclusion after testing other harnesses that had a greater number of stitches, and harnesses with a different arrangement of stitches.  The accident reconstruction expert’s laboratory tests found that harnesses with stitching like that in the decedent’s car failed when a force of 1,000 pounds was applied against them. In contrast to other harnesses with dissimilar stitching patterns that withstood a force of 3,000 to 4,000 pounds.

The court held that the testimony and evidence submitted through the expert witness was sufficient to submit the case to the jury to decide whether the shoulder harness was defective and whether the defendant manufacturer was liable for the racecar driver’s death.

Case Example: Sunbelt Envtl., Inc. v. Gulf Coast Truck & Equip. Co., Inc., 82 So. 3d 1196 (Fla. Dist. Ct. App. 2012)

In a personal injury action arising from a horrific accident in which a garbage truck struck a bicyclist, testimony from an accident reconstruction expert prompted the district court of appeal to reverse and remand the case. The circuit court had granted summary judgment in favor of the manufacturer of the truck and the installer of the tarping device placed on the truck to thwart debris dispersion.

However, the appellate court found that the testimony of the garbage hauler’s expert witness demonstrated that there was a genuine issue of material fact regarding the tarping unit in determining whether the installation of the tarp rendered the garbage truck wider than allowed by federal and state law. Moreover, the court found that the dispute is pertinent to the question of the proximate cause of the bicyclist’s injuries. The testimony of the accident reconstruction expert witness persuaded the court to hold that the circuit court had erred in holding that the truck manufacturer and tarp installer were not liable as a matter of law.

accident reconstruction expert witnessTrain Crashes

In litigation disputes following an accident involving a railroad, an expert witness with specific expertise in the railroad industry discusses applicable safety standards and trade practices.  Such testimony may describe how railroad companies typically program their crossing gate sensors to signal when a train is coming or discuss emergency braking mechanisms.

Case Example: Robinson v. Missouri Pacific Railroad, 16 F. 3d 1083 (10th Cir. 1994)

A tragic collision between a car and a train caused the death of a woman and her infant child.  In the wrongful death lawsuit, the court held for the plaintiff, finding that a faulty warning gate was 70% responsible for the accident. The court based this decision largely in part on testimony provided by the plaintiff’s accident reconstruction expert witness. The expert introduced an animated video depicting how the accident would have occurred based on the plaintiff and defendant’s respective case theory.  He testified to his conclusion that the models clearly supported the plaintiff’s theory.

Furthermore, the plaintiff’s accident reconstruction expert testified that based on the precise angle of impact, there was no evidence to support the defendant’s theory that the deceased had driven her car around the warning gate.  He noted that the train struck the vehicle at a perpendicular angle—the only angle consistent with the train pushing the car straight down the tracks until it came to a halt.  A second expert described the technical elements of the warning gate’s sensory system, concluding that the gate failed to work properly on the night of the crash.

Although the defendant appealed the judgment, arguing that plaintiff’s accident reconstruction expert witness provided a model based on “inaccurate” details.  Nevertheless, the court upheld the lower court’s ruling, finding that the lower court properly acted as a “gatekeeper” when considering all portions of the accident reconstruction experts’ testimony, including the animated video.

Vehicular Accidents

Accident reconstruction expert witnesses specializing in vehicles are essential in understanding a vehicular accident. Experts may opine on issues such as steering wheel angles, headlights, anti-lock braking systems, sudden acceleration, crash worthiness, or point of impact.

An accident reconstruction expert can provide testimony that refutes the opposing party’s case theory. For example, in a litigation matter where liability depends on which vehicle first entered the intersection, an expert witness may testify to a vehicle’s speed by explaining results of a coefficient of friction analysis. As speed data can be utilized to demonstrate which vehicle entered the intersection first, an expert witness can greatly influence the trier of fact’s decision.

Case Example: Com. v. Addy, 79 Mass.App.Ct. 835 (2011)

In litigation over liability in an accident that caused a motorcyclist’s death, the plaintiff’s expert witness, an experienced State Trooper who reported to the accident scene shortly after the accident, opined that the collision was caused by the defendant’s failure to stay within marked lanes.

The accident reconstruction expert testified that “while driving north on North Summer Street in [Berkshire County], the defendant left his lane of travel, crossed over a double yellow line, went into the southbound lane, and struck a motorcycle, resulting in the death of the motorcycle operator.”

The defendant argued that the plaintiff’s expert provided inadmissible testimony as to the cause and location of the accident.  The defendant filed a motion claiming that the Trooper’s testimony “was not reliable because he failed to utilize any scientific methods, analysis, or mathematical calculations in forming his opinion.”

However, the court noted that the defendant’s challenge was not about “the science of accident reconstruction…[but rather] that the motion judge and the trial judge erred by failing to determine whether Trooper Sanford, in reaching his opinion, correctly applied the science of accident reconstruction to the particular facts in this case in a reliable manner.”

In upholding the testimony of the plaintiff’s accident reconstruction expert , the court found that the Trooper’s “conclusions were based, in large measure, on the observations he made at the accident scene.” The Trooper, upon arrival at the scene observed the position of the vehicles as well as “gouge marks, scratches, and scuff marks…ordered photographs to be taken and later made measurements at the scene.

The expert’s testimony not only refuted the testimony of the defendant’s expert witness (who reviewed the accidence scene nine months following the accident) but persuaded the court to find the defendant guilty of negligently endangering the lives or safety of the public by operating a motor vehicle while intoxicated, failing to operate a motor vehicle within marked lanes, and causing the death of another person.

About The Author

Inna Kraner, J.D., is a Senior Business Proposals Specialist and writer with experience litigating corporate, industrial, financial, regulatory, and controversy matters.