Vehicle Accident Reconstruction
Automobile
Heavy Truck/Bus
Motorcycle
Pedestrian & Bicycle
PC-Crash Simulation
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is a list of some of the key areas in which the VSI Engineering
Division has specific experience. Please click on areas of interest
to learn more about our services and examples of case applications. |
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The VSI Engineering Division
specializes in automobile collision analyses. Impact severity and
time/speed/distance
results can
determine accident causation and liability issues as well as
provide critical information to the VSI Biomechanics Division
in order to assess occupant dynamics and injury mechanics.
The VSI accident reconstruction experts hold advanced engineering
degrees and have specialized training and experience to analyze
all types of automobile collisions including complex hi-speed
rollovers, multiple vehicle impacts, intersection collisions,
and low-speed impacts from all directions. Our analytical methods
and procedures, state-of-the-art computer technology (see
PC-Crash section), and sophisticated presentation skills combine to
offer an accurate and detailed understanding of how an accident
occurred
permitting our clients to assess their legal position.
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Time-Distance Analysis
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A
time/speed/distance analysis of the event provides valuable information
to assessing accident causation and liability issues. Click the smaller
image on the right to view an animation shown from one of the driver’s
perspectives.
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Unique
collision dynamics can be assessed using sophisticated engineering and
computer modeling techniques, our extensive library of crash test data,
or our full-scale and component testing capabilities. The images on the
left depict a part of a process of matching physical evidence using computer
scaling
overlay
techniques.
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(~7MB) |
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The above images depict
a reconstruction of a fatal high-speed, intersection collision. Quantifying
collision dynamics using physical evidence and scientific principles
not only demonstrates
accident causation issues but also provides impact severity data for
the damages phase of a case often involving biomechanical analyses of
occupant dynamics, restraint system use and effectiveness, and survivability.
Click the smaller image on the right to view an animation of this
high-speed impact based on documentation of vehicle crush/damage and
a momentum
based PC-Crash computer simulation matching known accident scene
data.
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Complex rollover
dynamics can be determined from close examination of vehicle-ground
contact evidence, vehicle dynamics knowledge, and computer simulation
techniques
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VSI engineers have specialized
training in the operation of commercial vehicles and the experience
to analyze the unique characteristics and dynamics of heavy truck
and bus accidents. Our computer simulation technology can be utilized
to conduct sophisticated reconstructions of vehicles ranging from
smaller trucks to large tractor-trailers.
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Specialized
training, advanced engineering dynamics, and sophisticated computer
simulation tools permit VSI engineers to analyze complex commercial
truck accidents.
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Computer
technology now permits simulation of complex vehicle dynamics
and rendering them as still or moving images to demonstrate critical
issues pertinent to the case. A computer model permits viewing from
various perspectives.
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This
highly specialized area requires knowledge
of both accident reconstruction scientific principles
and motorcycle dynamics.
VSI Engineer, Mr. Ed Fatzinger, has motorcycle expertise
including design, mechanical repair, and competitive racing.
He adds to this background
and knowledge specialized motorcycle accident reconstruction
techniques and computer simulation tools to provide state-of-the-art
motorcycle dynamics and collision analysis.
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VSI
engineer and accident reconstruction expert Ed
Fatzinger shown here during recent dirt track racing competitions
in California and Florida.
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    (~3.48MB)
Reconstruction
of accidents involving motorcycles requires specialized knowledge
and experience
regarding motorcycle-handling dynamics as well as accident
reconstruction principles. Shown above is a sequence from an
accident reconstruction assessing accident causation/liability;
in this case, impact location relative to the roadway center line.
Click the smaller image on the right to see a full-length animation
of
this
motorcycle
crash
reconstruction.
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Pedestrian vs. automobile and bicycle vs. automobile
impacts are best analyzed from the combined scientific perspectives
of accident reconstruction and biomechanics. The VSI Engineering
Division can analyze or measure various data critical to the assessment
of a pedestrian or bicycle impact analysis such as vehicle acceleration/braking
performance, driver or pedestrian or bicycle-rider visibility, and
model a range of impact configuration and speed scenarios using
computer simulation software. In combination with vital input from
the VSI Biomechanics Division regarding pedestrian or bicycle-rider
performance, impact position/posture, and injury dynamics, a total
reconstruction of the event can be compiled.
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Bicycle-rider
dynamics, truck dynamics, and precise scene information can be
combined to reconstruct and then demonstrate the accident event
including showing visibility from the various perspectives.
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Roll
over this image to view a simulation of a pedestrian accident
created with PC-Crash technology.
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PC-Crash is
one of the computer software programs utilized by the engineers
at VSI to simulate vehicle dynamics and collision
scenarios to assist with vehicle accident reconstructions. PC-Crash
was specifically developed and accepted in the scientific community
as a validated tool for many accident reconstruction applications.
This program permits custom input of vehicle specifications and
performance characteristics as well as detailed scene data to
assess case-specific three-dimensional dynamics. VSI engineers
have also developed advanced techniques to transfer three-dimensional
output from this program to sophisticated animation/graphic software
for image and movie rendering into high-quality presentations.
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Our
engineering and biomechanics staff have performed numerous crash
tests and published several technical papers based on our testing
results. We have the
capability and resources to perform a wide range of crash tests,
from low-speed to high-speed collisions.
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Click image
to watch video clip of a low-speed,
side impact crash test performed by VSI Engineers. (893KB) |
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Crash
Data Recorder (CDR) Retrieval - Testing & Technology
Many vehicles today
are equipped with a Crash Data Recorder (CDR). The CDR is a
device that records vehicle speed and acceleration. The CDR
also records operational data such as seatbelt status, airbag
deployment, brake application, throttle position and engine
RPM. In addition to the data collected at the moment of a collision,
several seconds of pre-collision data are also recorded.
During both low speed
impacts and high speed impacts, the data recorded by the CDR
can be downloaded from the CDR module. Even if only one of
the vehicles involved is equipped with a CDR, the data can
be used to determine the impact dynamics of the other vehicles.
The recovered data can then be incorporated into a collision
analysis that accurately depicts driver responses prior to
impact. The data retrieved can also provide information relevant
to an airbag deployment, or to evaluate a collision where deployment
did not occur.
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Laser
Technology Site Survey - Testing & Technology
Our laser survey equipment allows us to measure
an accident site or a vehicle and create a three dimensional
computer model for use in simulations, animations, and exhibits.
It can accurately measure road slopes, road curvatures, and
sight obstructions which can be difficult to measure by conventional
means. It also allows us to compare a damaged vehicle to
an undamaged exemplar vehicle in a scientific and repeatable
manner.
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Our
advanced systems and skilled engineering staff afford us the
tools necessary to perform a broad range of mechanical tests.
These tests include static or dynamic force measurements, acoustic
sound pressure levels in a car, as well as temperature/heat
transfer, friction, and light measurements.
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Above are
pictures and sample results from tests conducted by the VSI Biomechanics
Division on
seat belt anchors to match actual seat belt anchor deformation
from a high-speed frontal accident and thereby predict the seat
belt load (force) that occurred during the actual collision.
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Above are
photographs taken during drop tests onto windshields conducted
by VSI engineer, Mr. Ed Fatzinger, in
collaboration with the VSI Biomechanics Division to assess pedestrian
head impact dynamics, pedestrian kinematics, and vehicle
impact speed.
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In many cases, photographs
are the only recorded evidence from an accident or scene.
Close range photogrammetry can be critical
in determining important characteristics of such evidence
in order to facilitate an accurate analysis. Our engineers
are
skilled
in close range photogrammetry and use state of the art
software, computers, and equipment to ensure accurate and
correct results. Examples of applications of this technology
include establishing dimensions of accident sites that have
since been modified or no longer exist; detailed vehicle
crush measures when the subject vehicle no longer exists;
vehicle or human body points-of-rest; and relevant object
or human body dimensions. VSI engineers have even collaborated
with VSI biomechanists to determine precise three-dimensional
bullet entry and exit wound locations from autopsy photographs.
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Terrain
Modeling |
Photogrammetric
Analysis
of Crush Pattern |
Photogrammetric
Techniques
of Vehicle Crush |
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VSI’s Rapid Response Accident Investigation Team
has been called and responded within a few hours and/or few days
to the scene of numerous catastrophic accidents. In these situations
our team records and preserves physical evidence that is sometimes
only available at the scene within hours or days of the event,
which can be critical to assessing causation and liability issues.
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Above are
several images from a catastrophic accident in which VSI provided
rapid response
investigation.
The photograph on the bottom right shows VSI President Jeff Wheeler
identifying wreckage, in this case, remains of a freight trailer
on the day after
the accident.
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