The cast of experts in auto cases

An overview of the experts on liability and damages you might need to include in vehicle cases

Bill Karns
2015 May

This article broadly discusses the types of experts used in auto cases. There are, of course, cases that financially do not warrant hiring multiple experts. Practice tips are provided for those situations.

Accident reconstruction, biomechanics, human factors

The most common experts in auto cases are accident reconstructionists and biomechanical engineers. Accident reconstructionists can explain how the collision occurred by analyzing damage to vehicles, crash test data/dynamics, road markings (gouge marks, tread marks), police reports, other sources of physical evidence, and deposition testimony. Accident reconstructions can show who was at fault for a collision (who ran the red light etc.), and the forces involved in the collision. The forces involved in the collision are essential to the biomechanical analysis.

Biomechanical engineers explain how the forces of a collision (derived by an accident reconstruction) can cause injury to the occupants in a car. An expert in biomechanics can explain to a jury how a rear-end collision can cause neck and back injuries even in a low impact collision.

How quickly a driver reacts and sees things in the few seconds of a collision is often important in determining negligence and eradicating comparative fault. An expert in human factors can explain how quickly a driver can perceive and react to a particular condition.

For example, the defendant bus driver had plenty of time to perceive and avoid the impact, or the plaintiff could not perceive and react to defendant’s car running the red light in time to avoid the collision. Accident reconstructionists are generally aware of perception and reaction times and can testify on such issues, but their qualifications in the area of human factors may certainly be challenged. If the case is big with issues of perception and reaction, hiring a human factors expert along with an accident reconstructionist is recommended.

Auto MIST cases

Perhaps in no other case are we more financially limited in expert expenditures than in minor-impact-soft-tissue (MIST) auto cases. Expenditures on experts can quickly overtake the actual value of the case, potentially leaving your client with nothing. It usually is not economically feasible to retain a biomechanial engineer and an accident reconstructionist on a MIST case. While some attorneys disagree with this and will argue that only the biomechanical expert can explain to the jury how a minor impact can cause a major injury, going to trial with the treating physician (orthopedist, chiropractor) is often your only real option given cost and likely recovery.

Some insurance carriers will defend MIST cases with a slew of experts including radiologists, accident reconstructionists and biomechanical engineers in addition to orthopedists. Many of these areas of testimony can be addressed by a treating physician.

Despite popular belief, orthopedists are trained in biomechanics. Orthopedists are specifically trained and have extensive knowledge in what types of forces cause injury. What types of forces cause injury is biomechanics at its very core. The problem orthopedists have in giving an opinion on biomechanics only has to do with the actual term “biomechanics.” That word is not used in orthopedic residency. The concepts of the forces that cause injury certainly are.

Before expert discovery, sit down with your client’s orthopedist and explain that “biomechanics” simply refers to what types of forces cause certain injuries. With this understanding, an orthopedist will feel much more comfortable offering opinions on biomechanics.

Orthopedists are not going to be familiar with the most recent data and studies relating to biomechanics. This can be problematic. However, they can always fall back on their real world experience, their own study if you will, of treating thousands of patients injured in car accidents. Although it’s not very scientific, it can be powerful with a jury.

Damages experts

Damages experts will span a range of issues including the nature and extent of injuries, past and future medical expenses, lost earnings/earning capacity, causation and general damages.

Your client’s treating physician(s) will serve as one of your experts in virtually every auto case. Treating physicians can explain to a jury your client’s injuries including causation and prognosis. Some physicians have experience serving as experts in litigation. Others do not. Either way, it is extremely important to meet with your client’s treating physician for thorough preparation before designation and certainly before their depositions.

On injury cases where your client has permanent physical injury, chronic pain, and/or neurocognitive deficits, much of the economic damage will come from future medical care. Your job as the plaintiff’s lawyer is perhaps best described as identification and matching. You must identify which client will require future medical care and match the general type of care with the appropriate experts in developing a future medical care plan (commonly referred to as a life care plan). Identifying the client is relatively simple.

•Life care

If the injury permanently affects your client’s activities of daily living, your client will need a life-care plan. Certified life-care planners are experts in this field and are knowledgeable as to the costs of such future medical care. They are instrumental in developing a life-care plan.

Life-care plans do not end with the life-care planner. Life-care plans should be buttressed with the expertise of medical doctors who can work with your life-care planner to develop the plan. The type of medical doctor needed will depend on the injury.

If your client’s activities of daily living are affected by chronic pain, you should retain a pain management specialist to work with your life-care planner.

If your client’s injury is physical in nature, with motor deficits such as spinal cord injury, brain injury, etc., retain a physiatrist (physical medicine and rehabilitation) to work with your life-care planner. Traumatic brain injury will likely involve neurocognitive deficits, in addition to physical deficits, necessitating future care. Consider retaining neurologists and neuro-psychologists to address the neuro-cognitive issues in a life-care plan.

•Economists and Vocational Rehab

Generally, forensic economists and vocational rehabilitationists provide the expert testimony in the areas of lost earnings and loss of earning capacity. Economists can review past earnings records, along with nationally reported statistical data, to calculate your client’s lost earnings and loss of earning capacity.

Experts in vocational rehabilitation, who actually examine and test your client, can explain to a jury how your client’s injury prevents them from working. They can also show how your client’s condition prevents him or her from entering the workforce in the same field or a new field. Lost earnings and earning capacity can, and at times must, involve expert testimony. However, do not ignore the importance of testimony from co-workers and supervisors who worked day in and day out with your client. This testimony is free and powerful.

•Radiology: No evidence of injury

It seems the defense is designating radiologists on every case involving injury to the spine. Generally these experts will review the radiology films (X-ray/MRI) and testify there is no evidence on injury or acute injury on the films. Most of these radiologists are routinely used by the defense and subject to impeachment for obvious bias. Even so, the testimony can be very damaging to your case. It is also often the last testimony heard by the jury.

If the defense designates a radiologist, consider retaining your own radiologist and designating them as a supplemental expert for rebuttal purposes. This will allow you to call your radiologist as the last witness at trial. The opinions of your radiologist, as opposed to the Defendant’s, will be the last evidence heard by the jury before closing argument and deliberations.

It is important to explain to the jury through experts, including defense experts, that radiographic imaging is just that. Doctors do not treat medical imaging. Medical imaging does not show pain. Medical imaging does not show various types of injury. Medical imaging can never be used to say a plaintiff is not injured. Medical imaging can never be used to say a plaintiff is not feeling pain. Doctors never treat medical imaging. Doctors treat pain, and the pain was caused by the traumatic event/accident.


Picking the right experts for your case is not an easy task, especially where the value of the case does not warrant hiring multiple experts. While cutting corners with experts is not recommended, sometimes you got to do what you got to do.

[Note: Parts of this article were presented at the CAALA Vegas Convention in 2014 and/or appeared in Advocate April 2014.]

Bill Karns Bill Karns

Bill Karns is a partner at Karns & Karns. He focuses on major personal injury cases. He is on the Board of Governors of the Consumer Attorneys Association of Los Angeles (CAALA) and Consumer Attorneys of California (CAOC). In 2014, he was selected as a SuperLawyer. He also received the CAALA Presidential Award of Merit and the New Lawyers Division Chair Award of Merit in 2012 from CAOC.

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