|It is the morning of trial. You are well-armed as you ascend the
courtroom steps. You have retained the services of a superb accident reconstruction firm
which has prepared a computer-generated simulation which is dramatic, forceful and which
makes your point for trial far more eloquently than words possibly could. You can't lose.
Or can you? You may encounter an increasingly common problem. Your simulation may be so
dramatic, so forceful and so eloquent that the jury will never see it.
The advances in
computer technology in recent years are, of course, breathtaking. Through that technology,
the impossible becomes "reality." By means of computer imaging, volcanoes can
erupt in the middle of Wilshire Boulevard, dinosaurs can ravage San Diego, and sitting
presidents can "appear" in current films. (On the other hand, most
non-California residents probably feel the first two scenarios are not only possible, but
highly likely.) Indeed, this last example raises questions concerning the validity of
photographic evidence, long considered a standard and acceptable means of proof. There are
currently demonstrative evidence companies which advertise that they can, through computer
"enhancement," modify photographs to "recreate" a scene which no
When this technology is applied to the courtroom, it is an easy matter for counsel to
fall into the trap of permitting the "experts" not merely to reconstruct the
accident, but, instead, to create a scenario that finds little, or sometimes no,
evidentiary support. For example, if the issue in the case involves a motorcycle which is
alleged to have overturned during a routine maneuver, a traditional method of graphically
presenting the alleged product defect to the jury is through the use of a filmed or
In such a reconstruction, the assumptions of those who have set up the scenario are
readily discernible on the film or tape. The viewer can see the terrain, the speed of the
vehicle, the method by which the maneuver is executed, etc. More important, the
reconstruction happens in "the real world," i.e., what appears on the film or
tape actually happened.
Thus, if the party arranging for the demonstration cannot make the motorcycle actually
repeat what is alleged to have happened, this may be a powerful suggestion to that party
that the accident and resulting injuries may not have happened as alleged.
limitations do not apply with respect to a computer "enhanced" reality.
Depending upon the skill of the programmer and upon the assumptions applied to the
scenario, the computer-generated motorcycle can, quite literally, be made to do anything.
If the programmer wishes, the bike can be made not merely to flip over, but to execute a
complete gymnastics floor routine. Thus, the problem is that, through current computer
technology, a "reconstruction" may easily become a new "construction."
There is no question computer technology has a legitimate and important place in the
courtroom. It is extremely useful in giving the jury a visual presentation of matters
which are otherwise difficult or impossible to present in other graphic forms. For
example, the cause of an aircraft crash, the manner in which toxic waste allegedly
permeated soil or the present condition of a toxic spill are hard to present on tape or
film, but may readily be shown through computer-generated graphics. The problem that often
occurs is that counsel is unable to resist the siren call of the technical experts who can
urge the preparation of a more "compelling" presentation of an event than the
What counsel may forget is that this "high tech" evidence is subject to the
normal rules of evidence. The party offering the evidence must show relevance (Evid. Code
§§210, 351), lay foundation, and overcome any Evidence Code §352 objections. The first
prong is usually not at issue. Generally, the evidence offered is relevant to some
testimony or other evidence in the case. It is the latter two prongs which can be
A demonstration must be a fair representation of testimony or other evidence in the
case. To be admissible, the computer simulation, like other experimental evidence, must be
relevant, it must be conducted under "substantially similar conditions as those of
the actual occurrence," and the evidence must not consume undue time, confuse the
issues or mislead the jury. (Hasson v. Ford Motor Co., 19 Cal.3d 530, 548-550 (1977);
Culpepper v. Volkswagen of America Inc. 33 Cal.App.3d 510, 521 (1973).)
Thus, in order to be considered by the jury, the demonstration must be supported by the
evidence. It cannot consist of speculation. For example, in Long v. Cal.-Western States
Life Ins. Co., 43 Cal.2d 871 (1955), the trial court properly excluded evidence of an
experiment designed to show a gunshot wound could have occurred accidentally when the
decedent tripped where the tests were not made under conditions similar to those at issue.
The evidence was held to be too speculative based upon the available facts.
In Anello v. Southern Pacific Co., 174 Cal.App.2d 317 (1959), the Court of Appeal
concluded the trial court erred in admitting certain photographs of a train. The case
involved a train/automobile collision. The deceased driver's ability to see the train was
at issue, and the visual evidence depicted a train engine which did not correspond to that
in the accident: "The engine in the posed photographs is a diesel switch engine with
a flat front end painted a brilliant orange while the engine involved in the collision was
a black steam locomotive." (Id. at p. 322)
Counsel's error in the case was in trying to use the visual evidence, not to depict
what the scene looked like, but rather, to argue counsel's position by adding touches that
did not exist. This is a trap which must rigorously be avoided in the use of computer
Nor can a simulation simply ignore facts which have been conceded to exist. For
example, in the motorcycle example above, if the undisputed testimony was that at the time
the motorcycle fell, it was traveling on soft ground, sand or a wet surface, a proper
simulation would have to take that fact into account. If it fails to do so, it should not
go to the jury.
However, even assuming foundational problems are overcome, the attorney offering the
computer reconstruction must be prepared to deal with objections based upon Evidence Code
§352. Basically, the section provides that, notwithstanding the relevance of evidence,
the trial court, in the exercise of its sound discretion, may exclude it if the probative
value is substantially outweighed by the probability that admission will necessitate an
undue consumption of time, create substantial danger of undue prejudice, or create a
substantial danger of confusing or misleading the jury.
Normally §352 requires that the trial court engage in a balancing test and, if the
evidence is to be excluded, indicate on the record that the prejudicial impact of the
evidence significantly outweighs the probative value. By requiring the balance to tip more
heavily in the direction of prejudice, the section may be reconciled with the general rule
that all relevant evidence is admissible. (Evid. Code §351)
However, as a practical matter, a court assessing the impact of visual evidence in the
form of videotape or computer-generated simulations may require a lesser showing of
prejudice to conclude the prejudicial impact significantly outweighs the probative value.
This is so because of the power of such evidence to influence the trier of fact.
"A motion picture of the artificial recreation of an event may unduly accentuate
certain phases of the happening, and because of the forceful impression made upon the
minds of the jurors by this kind of evidence, it should be received with caution. As
pointed out by Wigmore, such a portrayal of an event is apt to cause a person to forget
that it is merely what certain witnesses say was the thing that happened' and may
impress the jury with the convincing impartiality of Nature herself.'" (People
v. Dabb, 32 Cal.2d 491, 498 (1948).)
This danger is intensified in the situation where a computer simulation is used. Not
only does the jury confront the impact of the visual presentation, but it must deal also
with the aura of credibility surrounding a simulation created by a computer. The computer,
of course, has no bias. It is not a retained expert. Among lay persons, a computer may be
perceived to have a level of reliability which is unwarranted by the competence and
assumptions of those who programmed the simulation. (Obviously, computer simulations raise
myriad issues concerning the breadth of discovery. Those issues are beyond the scope of
The result is that a court should subject such evidence to rigorous scrutiny before
allowing it to go to the jury. In this sense, counsel may find that the court will exclude
the evidence upon a lesser showing of prejudice than might be required with other types of
evidence. This should suggest two courses of action to the practitioner.
First, make sure the simulation adheres closely and relatively objectively to the
conceded facts and the facts which the evidence will support. Resist the temptation to
make the presentation argumentative or to add flourishes to the factual presentation. For
example, it will generally be unwise, as one practitioner in my court learned, to add
dramatic blood splatters to a simulation of an accident. (If blood evidence were relevant,
for example in a criminal case, then a simulation demonstrating such information could be
appropriate, although it might still raise serious §352 concerns with the court.)
Second, remember that most courts detest surprises during trial. This is especially
true of surprises that may entail forcing the jury to wait outside the courtroom while
matters which could have been considered before trial are determined. If you plan to use a
computer simulation, it is wise to advise the court of this before trial, at least by the
final status conference. If you spring the evidence at trial and there are significant
foundational and §352 issues which will consume a good deal of time to resolve, you run
an increased risk that the court will conclude under §352 that there will be an undue
consumption of time involved and exclude it. By bringing the court's attention to the
evidence before trial, you may also discern how willing the court is to permit such
evidence and, thus, avoid potentially embarrassing moments in front of the jury at trial.
Computer-generated simulations are a powerful tool. Their importance and use in
litigation will continue to increase as technology advances. However, before jumping in to
the "high tech" arena, counsel should be sure he or she knows the limits on the
use of such technology and communicates these limits to the experts who will be preparing
the evidentiary materials.
George P. Schiavelli is presiding judge of the
appellate division of the Los Angeles County Superior Court.