| Analysis of the collision may determine who or what was a proximate cause in the collision, exactly what occurred in the collision sequence and who had the best opportunity or last clear chance to avoid the collision. In the case of multiple impacts, CRA can determine the impact sequence, timing, actions and dynamics, as well as the damage and personal injury for each sequence or action.
What was the speed at impact? What were the actual events that transpired in the accident sequence? What would have occurred if a pre-impact travel speed or driver action had been different prior to the impact? CRA routinely answers these questions, in addition to many others.
Collision re-enactment
Collision re-enactment or dynamic illustration is possible in several ways. CRA can replicate the conditions of the collision and provide video and photographic documentation to determine the conspicuity of vehicles, pedestrians or objects. CRA can also conduct full scale crash testing to recreate certain crush patterns and impact forces. Computer Animation
Computer animated collision re-enactment is another way to illustrate how a collision occurred and what factors could have been changed to avoid the collision or to mitigate the injuries. |
Collision Avoidance Many factors can affect a driver's ability to perceive or predict the objects, obstructions or hazards present in the driving environment. Rain, fog, sunlight, darkness, external lighting, a considerable variation in object contrast, and other roadway traffic or physical features are just a few of the factors which must be considered during a reconstruction. The conspicuity of objects is a function of the contrast and illumination. To properly evaluate an event, we collect data to define the visibility parameters and conditions that the driver was operating under during the collision sequence. Obviously, a driver's ability to perceive and identify hazards is also a function of the human factors of that particular driver. Age, experience, eyesight, level of arousal, drug or alcohol ingestion, and medical conditions can all effect the probability of a driver to perceive an respond accordingly. CRA has expertise in identifying, categorizing, collecting and evaluating daytime and nighttime visibility factors and human factors interaction with those conditions. Metallurgy Often fractured or degraded mechanical components will be suspected in causing a collision. It is essential that the component be analyzed to determine the material properties, weld properties, strength and failure mechanism of the component. Our associates are top ranked mechanical engineers and metallurgist in the country. We have access to all of the state-of-the-art testing equipment for metallurgical analyses. Scanning Electron Microscopy In addition to our chemical and fatigue testing capabilities, CRA uses a scanning electron microscope to perform detailed investigations in material properties, failure of component parts and to prepare micrographs used in court to explain complicated structural analysis results. Statistical Evaluation Accident statistics give a great deal of information about a particular collision. It is possible to determine the frequency of similar collisions involving the same location or vehicle make, model or type. Variables can be controlled to determine the effect of particular changes in the accident history. CRA can access Texas and National accident databases to perform inquiries or statistical analyses of collision conditions. Computer Collision Reconstruction With the aid of various computer programs, it is possible to reconstruct the exact variables under which accidents occur. CRA can determine the speed of vehicles prior to impact, as well as the speed at impact. We are also capable of determining the exact angle at which impact occurred and the impact forces, for use in determining the occupant kinematics and injury causation. By evaluating physical evidence and/or vehicle event data recorder information, CRA can determine if and when brakes locked up, what steering inputs were applied by the driver, and how the vehicle responded to those inputs.
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Computer Collision Reconstruction (cont.)
The M-SMAC computer model is a time-domain mathematical model in which the vehicles are represented by differential equations derived from Newtonian mechanics combined with empirical relationships for some components (e.g., dimensional, inertial, crush and tire properties of the vehicles, the initial speeds, angles and driver-control inputs) that are solved for successive time increments by digital integration. The program, through step-wise integration of the equations of motion, produces detailed crash and post-crash time-histories of the vehicle trajectories, velocities, and accelerations, including the collision responses.
The user compares the M-SMAC-predicted trajectories and collision deformations with the physical evidence to determine the degree of correlation. Iterative runs can then be performed, varying initial speeds, heading angles and control inputs until an acceptable match of the physical evidence is achieved. The Vetronix Crash Data Retrieval (CDR) system utilizes Pre-Crash and Crash data from the vehicle's air bag module. The air bag module is the vehicle's “computer” that controls air bag deployment. Recordable air bag modules have been installed in select GM vehicles since 1990 and in select Ford vehicles since 1998. Click on images below to see examples of Vetronix Crash Retrieval Data.
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