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Attacking the defense biomechanical engineer.

The true junk science in auto cases comes from defense experts who claim that low-speed collisions don't cause injuries.

In low-speed collision cases in which vehicle damage is minimal, defense attorneys typically claim that a "minor" collision could not have caused the plaintiff's injury. In these instances, it is important to steer the jury away from this perspective to the more realistic view that it is impossible to predict how any given trauma or application of force will affect an individual involved in a low-speed crash.

San Antonio, Texas, is home base for Biodynamic Research Corp. (BRC). This organization is composed primarily of non-practicing physicians with bachelor's degrees in engineering who testify almost exclusively for the defense in low-impact collision cases throughout the United States.

Their core position concerning trauma-induced spinal injuries is that herniated discs can only occur as a result of "forces induced that are inconsistent with life"(1) and that the more common "whiplash"-type connective-tissue injuries will heal within six weeks of onset.

BRC's doctors and other defense-oriented biomechanical experts rely on the following "authorities," among others, to support the conclusion that low-speed impacts can never cause significant injury:

* Whitman E. McConnell et al., Analysis of Human Test Subject Kinematic Responses to Low Velocity Rear-End Impacts;(2)

* Whitman E. McConnell et al., Human Head and Neck Kinematics After Low Velocity Rear-End Impacts: Understanding "Whiplash";(3)

* Thomas J. Szabo et al., Human Occupant Kinematic Response to Low Speed Rear-End Impacts;(4) and

* D.H. West et al., Low Speed Rear-End Collision Testing Using Human Subjects.(5)

Each of these studies was conducted with a small number of human volunteers (seven or fewer) who knew full well that an impact was coming. The results of the studies cannot be projected onto the general population. The number of test subjects is not statistically significant, and the fact that they were prepared for impact nullifies the authors' conclusions.

The following articles critique the studies relied on by defense biomechanical experts and discuss valid research on injuries in low-speed collisions:

* Michael D. Freeman et al., Discrediting Defense Experts in Whiplash Cases;(6)

* Michael D. Freeman et al., "Whiplash Associated Disorders--Redefining Whiplash and Its Management" by the Quebec Task Force: A Critical Evaluation;(7) and

* G.P. Siegmund et al., Head/Neck Kinematic Response of Human Subjects in Low Speed Rear-End Collisions.(8)

If you have been unsuccessful in striking the defense biomechanical engineer in a pretrial hearing or during examination of the witness, you can use these articles as guides for dismantling the defense. They suggest several ways to attack defense experts on cross-examination or during direct examination of your own expert.

Raise the following issues when cross-examining the defense expert:

* First, ask the expert to justify the extrapolation of the studies' results. Press the expert to explain how the outcomes of carefully controlled crash tests with four to seven prepared, perfectly positioned, healthy male subjects can be applied to any other person, considering the infinite variability among humans.

* Second, emphasize the position of the injured occupant. For example, a turned head is a significant risk factor for injury. Ask the expert to turn his or her head as much as possible to one side and extend it backward. This is difficult to do, and the demonstration will show the jury why injury would be likely if a car occupant in this position received a frontal impact.

* Third, emphasize the position of the defendant driver. In most cases, this driver was moving forward at the time of impact. When the expert makes the point that this driver was not hurt, concede that the defendant driver, like the injured plaintiff, was probably not in an ideal position. However, again ask the expert to turn his or her head as much as possible, but this time flex it forward, demonstrating how the defendant driver's head would have moved. This will show the jury that flexing the head forward while turned is much easier than flexing it backward in the same position.

In testimony rebutting the defense expert's conclusions, your expert should make the following points:

* First, motor vehicles are designed to fail long after injury is possible in the human body. In other words, the target vehicle can absorb far more energy without damage than the human body can.

* Second, delta V (the change in speed of the struck vehicle at the time of impact) and acceleration values for the target vehicle can never be used to determine the precise forces that acted on the occupant.

* Third, minor body damage to the vehicles can often indicate that a great deal of energy was imparted on an occupant. If the energy is not absorbed by crush between the vehicles, then it is imparted to the occupant via the struck vehicle.

* Fourth, when little or no body damage occurs during the impact, the occupant accelerates more than he or she would have if the vehicles had sustained more damage. When there is damage to the vehicles, some of the energy of the striking vehicle is absorbed by the other vehicle before the occupant is accelerated.

* Fifth, a car's bumper ratings refer to the speed at which it can strike a fixed barrier without sustaining any permanent damage. When the vehicle strikes an elastic barrier, such as the bumper of another vehicle, the damage threshold goes up considerably. Many vehicles have bumper ratings of 2.5, 3.5, or 5 mph, which the defendant may cite as proof that the undamaged car must have been moving at a very low speed. But bumper-to-bumper collisions can easily exceed 10 mph without any resulting damage to the cars.

Themes and analogies

Using themes and analogies throughout the trial will help jurors understand why it is untenable for the defense to assert that injury was impossible in the crash. Consider the following suggestions.(9)

The eggshell concept. Common sense will tell the jury that you cannot determine the injury a crash victim has suffered by looking at the outer shell of the car. When we buy eggs, how often do we open the carton to check the eggs inside? Every time. You cannot determine the condition of the eggs by looking at the container.

Defense expert as lab rat. Ask the expert if he or she would mind adjourning to the parking lot and standing between two cars poised to collide at 5 mph.

Or ask the expert to consider the following experiment: Select someone outside the courtroom at random and, while the poor soul is distracted by the judge, the expert will charge into the unsuspecting "victim" and accelerate the person to 5 mph. (According to reliable sources, this was actually proposed in a trial, and the expert declined to participate because of the risk of injury and "liability concerns.") In other words, take the expert out of the safe confines of theory and into the real world.

The football helmet analogy. Ask the jury to imagine the following scenario: A stadium of previously noisy, screaming football fans goes deathly quiet. They are reacting to a frightening collision of players, helmet to helmet. The team doctor is attending to the injured player, Tom Smith, while players and coaches from both squads huddle around in fear.

A stretcher is called onto the field. Dad Smith runs out to check on his son. Tom says he has no feeling from his waist down. He cannot move his legs, and he is scared. As Tom is wheeled out to an ambulance, the doctor comes up to Dad, helmet in hand, and says, "Don't worry, Mr. Smith. Your boy could not have gotten hurt. See, there's not a mark on this helmet."

The concept of four fragile anatomy. We were not designed for vehicle crashes. We have a big, heavy head perched on a small neck made up of many components: bone, ligaments, muscles, nerves, and so on. A sudden, unexpected trauma, which these components are not designed to withstand, results in tearing, wrenching, and rupture. Multiple pain receptors are involved. All the injured, delicate components will, over time, be augmented with scar tissue, an unnatural condition. Permanent pain may be the consequence.

The Silly Putty analogy. One of the best demonstrations I have ever seen illustrating the effect of sudden trauma on connective tissue involved the use of Silly Putty. Connective tissue is like Silly Putty. A slow pull results in a measured, controlled stretch. But pull the substance apart with a quick jerk, and it snaps in two. No matter how slick the defense expert appears to be, he or she will have a hard time overcoming that visual demonstration.

Using concepts like these reminds the jury that we are not living in a controlled laboratory environment, as the defense biomechanical engineer would have us believe, but in the real world.

Challenge defense biomechanical experts in every aspect of their opinions. Keep an outline of the factors provided by Daubert and its progeny(10) that must be considered when evaluating the admissibility of an expert's opinions. Under Daubert, the judge must consider whether the expert's methodology has been tested, has been subject to peer review, has a known or potential error rate, and is widely accepted in the relevant scientific community. In a pretrial hearing, you can show the judge that the defense biomechanical expert's methodology does not meet Daubert's requirements for admissibility.

The "science" on which these experts rely is truly junk, and the testimony should be challenged.(11) If these experts are allowed to testify, show the jury how insupportable their opinions are, using good science and effective trial strategies.


(1.) Deposition of Dr. Richard Howard of BRC in In re Rattler, No. 94-CI-12882 (Tex., Bexar County Dist. Ct. Nov. 26,1997).

(2.) Society of Automotive Engineers Paper No. 930889 (1993).

(3.) Society of Automotive Engineers Paper No. 952724 (1995).

(4.) Society of Automotive Engineers Paper No. 940532 (1994).

(5.) ACCIDENT RECONSTRUCTION J., May/June 1993, at 22.

(6.) TRIAL, Mar. 1999, at 62 (adapted from Michael D. Freeman et al., A Review and Methodologic Critique of the Literature Refuting Whiplash Syndrome, 24 SPINE 86 (1999)).

(7.) 23 SPINE 1043 (1998).

(8.) Society of Automotive Engineers Paper No. 973341 (1997).

(9.) Many of these ideas come from other attorneys, whose suggestions are archived on the San Antonio Trial Lawyers Association list serve. See

(10.) Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579 (1993); General Elec. Co. v. Joiner, 522 U.S. 136 (1997); Kumho Tire Co. v. Carmichael, 119 S. Ct. 1167 (1999).

(11.) See Bruce H. Stern, Putting the Brakes on the Low-Speed Collision Defense, TRIAL, Jan. 2000, at 30.

David M. Adkisson is a partner at Adkisson & Adkisson in San Antonio, Texas.
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Date:Jun 1, 2000
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