A Computer Program for Accident
by Steve Belyus
presentations have to contain computer generated
information for a jury to take them seriously,”
commented a county prosecutor after I presented
my case for an aggravated vehicular homicide to
The case involved an elderly gentleman who had
been struck down by a pickup truck in his front
yard while he mowed his lawn. A young man
speeding down the street had run up behind a
slower vehicle and swerved to avoid striking it
in the rear, and subsequently lost control. The
truck careened across the yard and struck a
utility pole. The body of the victim was launched
30 feet before it touched down. The crash
investigation team determined the subject’s
pre-crash speed to be nearly twice the posted
limit. The prosecutor remarked that a jury would
be inflamed by this set of circumstances, because
“One doesn’t normally consider the hazard of
being run down by a motor vehicle while mowing
their lawn.” But he wanted a computer generated
display to present to the jury, and it was my job
to get him one.
I was aware of and impressed by the computer
generated displays and presentations at trials
shown on television, but as a Traffic Crash
Reconstructionist working for a law enforcement
agency, I didn’t have a budget for such extras.
While I had recently purchased a crime/traffic
scene CAD program named 3D EyeWitness, by
DesignWare Inc., I had never used the program and
was apprehensive that it might be too complex to
learn without investing a great deal of time and
effort. Even though I was a computer novice, I
soon learned that my fears were unfounded.
The program comes with an instruction manual
which guides the user step-by-step from
installation through its most complex functions.
A tutorial is provided to “get your feet wet”
before jumping into a project. You can create a
scene, modify it, and apply the various functions
that are supplied by the program -- and there are
There is a large library of drawing elements
to choose from, including a variety of cars,
trucks, people, and most items to be found at a
traffic scene. All are fully sizable.
For my first scene, I chose the permanent
fixtures and placed them in their proper
locations. Then I selected the non-permanent
fixtures (vehicles and pedestrian) and placed
them at their “at rest” location in the
drawing. I was quickly finished! A task which
would normally take hours of pencil dots and
compass arcs was completed in less than half an
hour the first time I had ever used the program.
The scene may be viewed from a variety of
altitudes in 2-D ranging from an aerial view to
one very close up. Work can be performed on the
scene from any of these allowing for very
meticulous placement during a close-up view. The
program provides a variety of options for
printing your work.
Once the scene is created in two dimensions,
you can move to the next function. With a click
of the mouse the 2-D rendering is transformed to
a 3-D external view (it takes less time than
Tyson vs. Seldon). Then you can move around the
perimeter of the drawing, viewing is from
different angles and altitudes. There are three
types of displays presented in the 3-D mode. The
“wireframe” displays each element as though
it were a 3-D model made of wire. This is the
Once the angle of view which you prefer is
found you may go to “hidden line” display.
This illustrates the scene from your chosen angle
as a 3-D sketch with all elements in proper
spatial proportion to each other. You can no
longer see through yourmodels and an object
located behind another object from the chosen
perspective is blocked from view.
The third display is a “painted” view. The
hidden line display is painted by the computer
with default colors. You can change and blend
colors on each element. I found that a 3-D
rendering of the 2-D sketch goes a long way
toward giving a jury a better feel for a sequence
of events. Everything is still to scale, only the
angle of viewing the scene has changed.
A power feature of the program is a 3-D
internal view. This function allows you to view
the scene in the same style as 3-D external with
the exception that your perspective is now from
within the scene itself instead of from the
perimeter. By controlling a camera icon you
determine the exact location, direction, even the
height and angle of the view from which you will
look. This function essentially places you inside
the drawing to look around.
I made extensive use of this during a work-up
on another crash in which a car struck a
pedestrian who crossed the street in its path.
The pedestrian’s claim that the car had to have
been speeding because it appeared so suddenly was
disproved by skidmark length and other physical
After first drawing the scene with the car and
pedestrian at their “time of impact”
locations I backed them up along their routes of
approach as ½ second intervals adjusting for the
varying speed of the car through the scene. At
each of these locations I checked the perspective
of both the driver of the car and the pedestrian
as though there were looking for each other. The
features of the program allowed me to adjust for
the eye level of the driver seated in the car as
well as the pedestrian (knowing his height) both
as he walked across the street and before he
stepped into the street from the elevated
This series of scenes showed that the views
the driver and pedestrian might have had of each
other was obscured by a vehicle from which the
pedestrian had just exited. As that vehicle
pulled into the street and moving toward the
oncoming car, it blocked their view of each
Other positive attributes of the program are:
• Accurate measurements can be made on the
screen from point to point.
• You can draw and include in a scene an
element that isn’t provided in the library.
• Scenes can be adjusted for the proper
location and angle of the sun.
The license permits the “use the software on
any compatible computer, provided you use the
software on only one computer at a time.” This
makes it convenient to take a project to court
and load it into their computer to display and
manipulate during a hearing.
While the program was developed to deal with
both traffic and crime scenes, the library for
crime scenes is more elaborate, enabling the
construction of a multiple story house complete
with furniture, fixtures, personal effects and
even yard elements. After building a house and
yard you can view it from any angle or location,
inside and out. Weapons, people, contraband,
bullet holes, etc. may be positioned
appropriately. You can even look through the
windows to see objects on the other side.
MovieMaker allows you to move through these
scenes as well.
The few negative experiences I have
encountered include: when you print a “painted
line” version of a diagram as viewed from an
angle, the printout appears skewed. Also, the
program will only display items from the library
in 3-D. Elements created with the “draw”
function do not appear.
A very positive attribute of this program is
This program gave me a tool that I never
anticipated for doing work that I have never
considered. I have used it heavily and I am still
coming up with new ideas for applications.
Sgt. Steve Belyus serves with the Ohio State
Highway Patrol in the division’s Crash
Reconstruction and Analysis (CRA) section.