Records to subpoena, deposition outline, practice pointers.

by Steven R. Young and Michael R. Melton

Excerpted from Medical Proof of Whiplash

The defendant’s biomechanical expert (and the defendant’s orthopaedist) pose the greatest problem for counsel trying a MIST case or a TBI resulting from retraction mechanism case. [“Retraction mechanism injury” is the better description of the mechanism of whiplash. “Whiplash” is the defense industry euphemism for the injuries caused by the retraction mechanism.] The most effective way to counter the evidence from these witnesses is to prevent them from testifying. To exclude the testimony, you must conduct a deposition that demonstrates the “expert” is unqualified to give expert opinion.

§1531.2 Subpoena Records

To prepare for the biomechanical expert’s deposition, review the expert’s resume and send subpoenas to each school the expert attended and to any schools or institutions at which the expert claims to teach.

Subpoena the following records from each university the biomechanical expert witness attended:

  • The entire student file for [Biomechanical Expert], including class transcripts and grades received;

  • All materials concerning post-graduate degree dissertations or theses by [Biomechanical Expert] related to: Ph.D. in Biomechanical Engineering and/or MS Engineering;

  • Course Catalog for Engineering Department for the years     to    ; and

  • Course Catalog for Biomechanical Engineering Department for the years     to    .

Practice Pointer:

Catalog reveals nature of course work

The reason for requesting the course catalog is to learn the nature of the courses the expert took. Reviewing the types of courses the Expert took may reveal that the Expert took no courses relevant to the opinion that the Expert is offering. Often, a course’s title may sound relevant, but reference to the catalog will show the course is not relevant. Don’t use this at the deposition to impeach, but save it for the motion in limine to preclude the expert’s testimony.

Subpoena the following records from any university or institution at which the expert claims to teach or to have taught at previously.

  • The entire personnel file, including employment contracts, reviews, payroll and other information concerning [Biomechanical Expert] (who claims to be a professor teaching [Biomechanical Engineering] and [Mechanical Engineering] at this institution).
  • Course Catalog for Engineering Department.

§1531.3 Deposition Outline


Save impeachment evidence for trial

Deposition is not the time to cross-examine an expert with impeachment evidence. Impeachment only counts at trial. Impeachment during deposition does nothing but educate the expert, give the expert notice of what you have on him, and allow the expert to prepare to deflect the impeachment evidence at trial. If you have impeachment evidence on the expert, keep it in your briefcase to use at trial. Many attorneys have an irresistible impulse to impeach during deposition. Resist the impulse.

Q:    Please define “Delta V.”

Practice Pointer:

Velocity, not speed

“Delta V” means change of velocity. Some speak of it as a change of speed. It is not. Velocity is a vector quantity, and speed is a scalar value.

Q:    Define “acceleration pulse.”

Practice Pointer:

Brief explanation of “acceleration pulse”

If I hit a brick wall doing 100 mph, my car’s speed goes down immediately—a negative acceleration. The time during which the negative acceleration (deceleration) occurs is the “pulse.” When I hit the wall, the negative acceleration pulse is very brief, perhaps 60 milliseconds. In 60 milliseconds my car goes from 100 mph to zero mph. You can imagine what happens to the car, or to me if I am without an air bag and seatbelt. Contrast this with my deceleration from 100 mph when I gently apply the brakes: the negative acceleration pulse is several seconds, not milliseconds. My car comes to a gradual stop with no injuries.

When a defendant strikes a stationary plaintiff’s car from the rear, plaintiff’s car accelerates from an initial zero mph to a higher speed. Physicists measure acceleration in g’s. A “g” is a “gravity.” Gravity, according to Einstein, is actually a function of acceleration. One g means an acceleration of 32.2 feet per second per second; this is the same rate at which you accelerate in free fall. Five miles per hour converts to 7.35 feet per second. If a rear-ended car accelerates from zero to 5 mph in 0.100 seconds, we divide 7.35 by 0.100 and we get 73.5. We divide 73.5 by 32.2 (the value of one g) and we get 2.28 g’s. This value, 2.28 g’s, is the average acceleration of the plaintiff’s car. The peak acceleration would be about double the average, that is, about 4.6 g’s is peak acceleration.

Volvo has conducted many tests on retraction mechanism injuries and how to mitigate them in rear-end crashes. In its research, Volvo found the shape of the acceleration pulse is quite significant because a narrower pulse (acceleration occurring over less time) increases the relative movement of the lower cervical spine before the head contacts the headrest. Olsson, Ingemar, et al, Volvo Safety Report, An In-Depth Study of Neck Injuries in Rear End Collisions, 1990 International IRCOBI Conference, September 12- 14, 1990, Bron, Lyon, France, p. 10.

What is considered by some to be most significant in producing neck injury is not head acceleration, but lower neck acceleration at the T1 vertebra. This acceleration, which is greater in magnitude than the acceleration of C1 or the head center of gravity during the initial stages of the crash, gives rise to the so-called retraction injury mechanism.

Q:    Did you estimate the acceleration pulse for this crash?

Practice Pointer:

Longer acceleration pulse, lower average acceleration

Because stretching the time lessens the severity of the crash, the crash can be “hard” and end very soon, at 100 milliseconds or much “softer” and end at 125, 150 or even 200 milliseconds. The longer the acceleration pulse, the lower the average acceleration (and usually the lower the peak acceleration), and presumably the less severe the crash as far as neck injury potential is concerned.

Q:    What did you estimate the acceleration pulse for this crash to be?

Q:    Tell me all factors you considered to estimate the acceleration pulse.

Q:    What period did you use to calculate the acceleration pulse?

Q:    Why did you select that period?

Q:    Why did you not select a longer period?

Q:    Isn’t it true that if you select a longer period that the acceleration pulse is lower?

Q:    Likewise, isn’t it true that if a shorter period is used, the acceleration pulse is greater?

Q:    Isn’t it true that unless you actually instrument the car, you have no idea exactly what the shape of the acceleration pulse will be?

Q:    Did you use the Insurance Institute for Highway Safety crash test databases in any aspect of your work on this case?

Q:    Which database?

Q:    Did you calculate Energy Equivalent Speed (EES)?

Practice Pointer:

“Barrier equivalent speed”

EES is also referred to as Barrier Equivalent Speed. Some think of it in terms of the speed at which a body impacts another object. A higher EES does not correlate with increased injury potential. If you show a jury a photo of the rear end of a car which is ostensibly undamaged versus a photo of a car which is obviously severely crushed, intuition would suggest that the severely crushed car should be the one in which the driver was more likely to suffer injury. Not always true! This is another reason why photos of the rear of a plaintiff’s car are misleading to a jury if the photos show little damage. The less-damaged car can be the result of the more injury-producing crash event for the driver. Volvo’s studies found there is no correlation between the duration of neck injury symptoms and the EES. Volvos with some of the worst damage and largest EES values had the least driver retraction mechanism injuries, probably due to deflection of the seat back rearward and resulting attenuation of the retraction mechanism response. Olsson, Ingemar,, Volvo Safety Report, An In-Depth Study of Neck Injuries in Rear End Collisions, 1990 International IRCOBI Conference, September 12-14, 1990, Bron, Lyon, France, p.7.

Volvo issued numerous press releases stating that retraction mechanism injury is most likely to occur in low speed collisions. Fallon, Jeannine and Hammond, Fred, Press Release, Volvo Head Restraints Receive Top Honors From IIHS—Again, Release No. V7-24, April 1997, Volvo Cars of North America, Inc. (EP). Volvo and the Insurance Institute for Highway Safety, which is supportive of Volvo’s retraction mechanism research (Insurance Institute for Highway Safety,Whiplash Injuries Much Less Likely to Occur in Cars with New Seat/Head Restraint Combination, Advanced Crash Tests Show, IIHS News Release, December 8, 1998. (EP)), know full well that lack of apparent bumper damage does not mean the driver could not have been hurt, and it may actually mean he was more likely to have sustained retraction mechanism injury than would have been the case in a more severe rear end impact.

Q:    Did you utilize any data or information from Neptune Engineering?

Practice Pointer:

“Stiffness data” is unreliable

Neptune Engineering sells A/B stiffness coefficient data which is based on certain assumptions about the onset of damage speed (although for a few vehicles the onset of damage speed is known from IIHS tests). Depending on how these assumptions are manipulated, the values of the A/B coefficients for a particular car can fluctuate substantially. Because of the intrinsic unreliability of stiffness data at very low speeds, no reputable accident reconstructionist would use such data in a case where there is almost no permanent, measurable crush. Although the Neptunedatabase is excellent, it is often misused. In low speed, rear-end crashes it should not be used at all in most cases.

Q:    What type of front bumper did Defendants’ car have? [Honeycomb bumpers, foam core bumpers?]

Q:    Do you know if Plaintiff’s car had energy-absorbing bumpers?

Q:    Did you measure the “stroke” of the energy absorbing bumper isolators in Defendant’s car?

Practice Pointer:

Bumper damage unrelated to injury

This series of questions relating to damage and bumpers is important. Many defense experts erroneously or deceitfully assert that a particular crash could not have produced sufficient “energy transfer” to cause injury because the rear of the plaintiff’s car doesn’t appear to be seriously damaged. Some even go so far as to make such opinions from photographs of the cars. Matsushita, et al “tested human volunteers at a 3 mph Delta V, and six of them experienced neck pain for up to four days.” Matsushita, et al, X-Ray Study of the Human Neck Motion Due to Head Inertia Loading, Technical Paper #942208, Society of Automotive Engineers, 1994, page 63. A Delta V of 3 mph results from a barrier crash of about 2 to 2.5 mph. Every production vehicle can tolerate such a crash without any bumper damage.

In a crash, the cars don’t necessarily absorb energy equally. When energy is “absorbed” work is done on the metal to crush it. The stiffer car will crush less than the softer car, but the stiffer car, although ostensibly not crushed, can have a very severe acceleration pulse felt in the passenger compartment. Volvo has recognized this and has declared that crash pulse shape is more important in injury assessment than energy transfer. Olsson, Ingemar,, Volvo Safety Report, An In-Depth Study of Neck Injuries in Rear End Collisions, 1990 International IRCOBI Conference, September 12-14, 1990, Bron, Lyon,France, page 10.

Q:    Do you know if Plaintiff’s vehicle was equipped with onboard crash event recorders built into the main computer?

Q:    Do you know what an automotive onboard black box is?

Q:    What is it?

Q:    Do you know whether either Plaintiff’s vehicle or Defendant’s vehicle had a black box?

Q:    Did either vehicle have a black box?

Q:    Do you know whether any party took steps to collect data from the onboard black box for either vehicle?

Q:    Were you able to recover any information from either onboard black box?

Q:    What data were you able to recover?

Q:    Did you use the data in making your calculations?

Q:    Did you choose to reject data from the onboard black box in making your calculations?

Q     What information did you elect not to use in making your calculations?

Q:    Why did you decide not to use data from the on board black box?

Q:    Did you examine any onboard equipment from Defendant’s vehicle?

Q:    Did you examine any onboard equipment from Plaintiff’s vehicle?

Q:    Did you calculate acceleration pulse for the crash between Plaintiff and defendant?

Q:    What factual data did you collect to enable you to calculate acceleration pulse for the crash between Plaintiff and Defendant?

Q:    Do you know what “backset” is?

Practice Pointer:

Headrest position

A backset is the horizontal gap between the back of the head and the headrest. The backset is important because the distance the plaintiff’s head travels in the retraction mechanism injury bears a significant role in the severity of the retraction.

Q:    How does backset affect the severity of the impact of a subject’s head against a headrest? Did you collect any data concerning the backset for Plaintiff immediately before the crash?

Q:    Did you make any assumptions about the backset for Plaintiff immediately before the crash?

Q:    State all the assumptions you made about the backset for Plaintiff immediately before the crash?

Q:    State the basis for each assumption you made about the backset for Plaintiff immediately before the crash.

Q:    Did you perform an accident reconstruction for the crash?

Q:    Identify each crash dynamic that is a component of the accident reconstruction you performed.

Q:    Describe the condition of the Plaintiff’s automobile.

Q:    Describe the condition of the Defendant’s automobile.

Q:    Did you calculate the Delta V for the crash?

Q:    List all physical evidence that you relied on to calculate the Delta V for the crash.

Q:    State all assumptions you made in connection with the Delta V calculation.

Q:    Tell me how you performed the calculation of Delta V for the crash.

Q:    In your opinion of the Delta V for the crash, what is the margin of error?

Q:    What is your opinion of the Delta V for the crash?

Q:    Did you perform a crash injury reconstruction?

Practice Pointer:

Study of occupant kinetics

Crash injury reconstruction is a study of occupant kinetics, i.e., the forces on, and movements of, the bodies inside the car during the crash. Many “laymen” with no medical training purport to render a medical opinion in terms of the mechanism of injury. At the deposition, get every bit of this evidence out that you can. At trial, move to exclude it all on the ground that the biomechanical expert cannot render a medical opinion because he lacks medical training. The predicate for exclusion is that the biomechanical expert has not taken any relevant medical courses. So the next question is:

Q:    Please tell me all courses, seminars or other training you have had in the area of 1) anatomy, 2) physiology, 3) anatomical kinetics?

Q:    Did you review any doctor’s diagnosis of injuries resulting from the crash?

Practice pointer:

Grounds for excluding testimony

An expert can rely on the opinions of other experts, and on hearsay and other inadmissible evidence. In the area of crash injury reconstruction, you need to have the expert catalog everything the expert has seen and considered. This is essential as an exclusion tool. If the expert has not considered any doctor’s diagnosis or records, you need to tie the expert down to this, and then make this the basis of excluding the crash injury reconstruction. Likewise, when you are preparing your case for trial, you need to assure that you have an expert that either has the medical training to testify to crash injury reconstruction, or that the necessary medical materials and supporting opinions from a doctor are in the hands of your expert.

Q:    Did you identify any injury mechanisms arising from the crash in relation to estimated Delta V that explain how the injuries diagnosed by the doctor were caused by the crash?

Steven R. Young is different from other litigators because he takes cases to trial. Since 1983, when he tried his first case, Mr. Young has taken more than one hundred cases to trial, with most of these tried to a jury. His no-nonsense approach to case preparation and motion practice has resulted in numerous multi-million dollar verdicts and settlements in favor of his clients.  Mr. Young practices in Irvine, California.

Michael R. Melton has been immersed in the field of whiplash injuries for more than a decade. He wrote and published his first book, The Guide to Whiplash, in 1995. The following year, he started a newsletter for professionals who work with personal injury cases, the Injury Resources Monthly. In recent years Mr. Melton has written and produced a variety of materials in different media that make it easy to explain injuries to lay people. Mr. Melton is the owner of BodyMind Publications (

They are the authors of Medical Proof of Whiplash,from which this article is excerpted.