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Technical Paper

Use of Monte Carlo Simulation Techniques in Accident Reconstruction

1994-03-01
940719
This paper describes a straight-forward, automated approach to performing sensitivity analyses using Monte Carlo simulation techniques. Probability distributions are assigned to key input parameters, and results are expressed in the form of probability distributions of each of the desired output parameters. ...The approach is fast and automated, and provides a rational basis for dealing with uncertainty and ranges of parameters in accident reconstruction analyses.
Technical Paper

Considerations for Applying and Interpreting Monte Carlo Simulation Analyses in Accident Reconstruction

2007-04-16
2007-01-0741
One popular method of examining and quantifying the uncertainty within an analysis is the use of Monte Carlo simulation techniques. The methods have been well established and published over the last several years by numerous authors. ...One of the key factors underlying the Monte Carlo analysis is the assumed probability distribution of the individual factors within the analysis. ...However, the literature to date has not examined how the assumption of a distribution affects the resulting probability distribution of the Monte Carlo analysis. This paper attempts to address this issue. Furthermore, with the large number of samples typically considered during a Monte Carlo analysis, the resulting probability distribution tends to be normal and lends itself well to statistical interpretation as to the “most likely” range of the desired parameter.
Journal Article

Sensitivity of Monte Carlo Modeling in Crash Reconstruction

2010-04-12
2010-01-0071
The Monte Carlo method is a well-known technique for propagating uncertainty in complex systems and has been applied to traffic crash reconstruction analysis. The Monte Carlo method is a probabilistic technique that randomly samples input distributions and then combines these samples according to a deterministic model. ...The Monte Carlo method is a well-known technique for propagating uncertainty in complex systems and has been applied to traffic crash reconstruction analysis. ...The computed sensitivity values were obtained using analytical derivatives which only required a single Monte Carlo simulation. The analytical derivative values are compared to a finite difference value to demonstrate numerical accuracy.
Technical Paper

Monte Carlo Simulation Methods Applied to Accident Reconstruction and Avoidance Analysis

1994-03-01
940720
In this paper Monte Carlo simulation methods are applied to accident reconstruction and accident avoidance analysis. ...When reconstructing vehicle accidents it is necessary in the course of the analysis to account for the uncertainty in the values of the key parameters such as tyre to road adhesion, the direction of vehicle movement both pre- and post-impact etc. ...Also the benefits which can be obtained from redundancy of the relationships describing the particular accident are examined. The results which can be obtained are demonstrated by a number of case studies.
Technical Paper

Application of the Monte Carlo Methods for Stability Analysis within the Accident Reconstruction Software PC-CRASH

2003-03-03
2003-01-0488
As in most accident reconstruction cases, several parameters, like ground friction or inter-vehicle friction are not well known, as well as many vehicle or driver related parameters. ...A method was developed, which allows one to vary multiple parameters based on a Monte Carlo method. The error within the fulfillment of the target function can thus easily be used as a quality indicator for the selected initial conditions. ...Two algorithms are presented, both based on the Monte Carlo approach. The first one serves as an alternative for the optimizer tool and is included in the current version of PC-Crash.
Journal Article

Monte Carlo Techniques for Correlated Variables in Crash Reconstruction

2009-04-20
2009-01-0104
Therefore, a discussion of uncertainty propagation techniques with correlation and Monte Carlo simulation of correlated variables is presented in this paper. The idea that measuring a parameter with a common instrument induces correlation is explored by examining the process of determining vehicle weights. ...However, the examples provided are aimed at introducing the concept of correlation in Monte Carlo simulation and determining the practical significance of correlation have yet to be determined. ...Furthermore, interpreting and presenting results from simple Monte Carlo analysis of a momentum problem requires using the concepts of joint, marginal, and conditional distributions to fully understand the results.
Technical Paper

Conducting Monte Carlo Analysis with Spreadsheet Programs

2003-03-03
2003-01-0487
Monte Carlo analysis has been shown to be a powerful tool for evaluating confidence limits and probability distributions for values calculated during the analysis of vehicle accidents. ...This paper presents a method of using the tools provided with most simple spreadsheet programs to conduct Monte Carlo analysis with both evenly distributed and normally distributed variables for cases where the equations can be expressed in closed form. ...Monte Carlo analysis has been shown to be a powerful tool for evaluating confidence limits and probability distributions for values calculated during the analysis of vehicle accidents. Using this tool has generally required specialized software. This paper presents a method of using the tools provided with most simple spreadsheet programs to conduct Monte Carlo analysis with both evenly distributed and normally distributed variables for cases where the equations can be expressed in closed form.
Technical Paper

Uncertainty in Accident Reconstruction Calculations

1994-03-01
940722
Three popular techniques are discussed in the context of accident reconstruction. The first establishes upper and lower bounds through calculation of the largest and smallest possible values of the quantity being estimated for all combinations of the input variables.
Book

Collision Reconstruction Methodologies Volume 6A: Rollover Accident Reconstruction

2018-11-02
Because of the technological changes occurring in the industry, many SAE papers have been written to address the validation and use of new tools for collision reconstruction. Collision Reconstruction Methodologies Volumes 1-12 bring together seminal SAE technical papers surrounding advancements in the crash reconstruction field. ...Topics featured in the series include: • Night Vision Study and Photogrammetry • Vehicle Event Data Recorders • Motorcycle, Heavy Vehicle, Bicycle and Pedestrian Accident Reconstruction The goal is to provide the latest technologies and methodologies being introduced into collision reconstruction - appealing to crash analysts, consultants and safety engineers alike. ...The last ten years have seen explosive growth in the technology available to the collision analyst, changing the way reconstruction is practiced in fundamental ways. The greatest technological advances for the crash reconstruction community have come in the realms of photogrammetry and digital media analysis.
Technical Paper

Integrating Monte Carlo Simulation, Momentum-Based Impact Modeling, and Restitution Data to Analyze Crash Severity

2001-10-01
2001-01-3347
Accurate evaluation of the crash severity will, therefore, include analysis of the effect that uncertainties in the values of the input parameters have on the calculated change in velocity. Monte Carlo simulation, a statistical technique, enables the reconstructionist to evaluate the effect of uncertainty on the analysis of crash severity. ...Use of the Monte Carlo simulation technique is beneficial since a reconstructionist can enter a range of values for each input parameter. ...Application of the Monte Carlo technique is intended to improve the legitimacy of crash severity analysis by helping the reconstructionist consider a wide range of possible solutions within the bounds of the imperfect data and report statistically meaningful ranges for the change in velocity.
Journal Article

A Bayesian Approach to Cross-Validation in Pedestrian Accident Reconstruction

2011-04-12
2011-01-0290
In statistical modeling, cross-validation refers to the practice of fitting a model with part of the available data, and then using predictions of the unused data to test and improve the fitted model. In accident reconstruction, cross-validation is possible when two different measurements can be used to estimate the same accident feature, such as when measured skidmark length and pedestrian throw distance each provide an estimate of impact speed. ...In accident reconstruction, cross-validation is possible when two different measurements can be used to estimate the same accident feature, such as when measured skidmark length and pedestrian throw distance each provide an estimate of impact speed. ...An actual measurement falling in an extreme tail of the predictive distribution suggests a weakness in the assumptions governing the reconstruction. This paper describes an implementation of these ideas using the Bayesian freeware WinBUGS.
Technical Paper

Evaluating Uncertainty in Accident Reconstruction with Finite Differences

2003-03-03
2003-01-0489
The most effective allocation of accident investigation resources requires knowledge of the overall uncertainty in a set of calculations based on the uncertainty of each variable in real-world accident analyses. ...The most effective allocation of accident investigation resources requires knowledge of the overall uncertainty in a set of calculations based on the uncertainty of each variable in real-world accident analyses. Many of the methods currently available are simplistic, mathematically intractable, or highly computation-intensive. ...In this way, greater efforts in an accident investigation can be directed to the most influential of the measurements, while less effort need be expended on the values which have trivial effect on the analysis results.
Book

Collision Reconstruction Methodologies Volume 8: Error Analysis and Uncertainty in Accident Reconstruction

2018-11-02
Because of the technological changes occurring in the industry, many SAE papers have been written to address the validation and use of new tools for collision reconstruction. Collision Reconstruction Methodologies Volumes 1-12 bring together seminal SAE technical papers surrounding advancements in the crash reconstruction field. ...Topics featured in the series include: • Night Vision Study and Photogrammetry • Vehicle Event Data Recorders • Motorcycle, Heavy Vehicle, Bicycle and Pedestrian Accident Reconstruction The goal is to provide the latest technologies and methodologies being introduced into collision reconstruction - appealing to crash analysts, consultants and safety engineers alike. ...The last ten years have seen explosive growth in the technology available to the collision analyst, changing the way reconstruction is practiced in fundamental ways. The greatest technological advances for the crash reconstruction community have come in the realms of photogrammetry and digital media analysis.
Standard

Ethics for Accident Investigation and Reconstruction

2011-02-18
CURRENT
J2314_201102
The purpose of this SAE Recommended Practice is to promote the highest professional and personal conduct of practitioners in the fields of accident investigation and reconstruction. It encourages the continuous application of high ethical principles to one’s own endeavors. ...It also encourages the application of these same principles to others associated with accident investigation and reconstruction.
Technical Paper

The Practical Application of Finite Difference Analysis in Accident Reconstruction

2007-04-16
2007-01-0713
The effective application of a Finite Difference Analysis routine in accident reconstruction is demonstrated. Such analysis finds not only the central value but the reliability side-bands; not only the mean but the probable extremes of the analysis, given the probable investigative reliability. ...Furthermore, because the controlling transfer functions depend only on the physics of the event, the side-band spans found by one means of reconstruction apply also to the central values found by some other means. Such ubiquity allows the practitioner to add to pre-existing central results the probable bounds of those results due to the practical limitations of investigative accuracy.
Technical Paper

On the Concept of Inter-Vehicle Friction and Its Application in Automobile Accident Reconstruction

2007-04-16
2007-01-0744
Occasionally, an accident reconstruction analyst is confronted with the task of reconstructing an accident with configurations that do not lend themselves to straightforward analytical methods. ...The analyst may often turn to accident reconstruction software such as the various versions of SMAC and some impulse-momentum approaches like PC-Crash and VCRware. ...This can lead to the modification of the inter-vehicle friction value to tune the simulation result; typically in an effort to force the final rest positions of the collision partners to match documented accident scene evidence. In this paper, the concept and application of the inter-vehicle friction coefficient is examined.
Book

Vehicle Accident Analysis and Reconstruction Methods, Second Edition

2011-04-12
Thoroughly revised, this new edition builds on the original exploration of accident analysis, reconstruction, and vehicle design. Enhanced with new material and improved chapters on key topics, an expanded glossary of automotive terms, and a bibliography at the end of the book providing further reading suggestions make this an essential resource reference for engineers involved in litigation, forensic investigation, automotive safety, and crash reconstruction. ...Designed for the experienced practitioner, this new book aims to help reconstruction specialists with problems they may encounter in everyday analysis. The authors demonstrate how to take the physics behind accidents out of the idealized world and into practical situations. ...The authors demonstrate how to take the physics behind accidents out of the idealized world and into practical situations. Real-world examples are used to illustrate the methods, clarify important concepts, and provide practical applications to those working in the field.
Technical Paper

Evaluating the Uncertainty in Various Measurement Tasks Common to Accident Reconstruction

2002-03-04
2002-01-0546
This paper presents the results of recent tests conducted to obtain sample distributions of some common parameters, including measurements made with tapes, measurements made with roller-wheels, skidmark measurements, yawmark measurements, estimation of crush damage from photographs, and drag factors, that can be used to evaluate the uncertainty in an accident reconstruction analysis. The paper also reviews the distributions of some pertinent data reported by other researchers. ...When performing calculations pertaining to the analysis of motor vehicle accidents, investigators must often select appropriate values for a number of parameters. The uncertainty of the final answers is a function of the uncertainty of each parameter involved in the calculation.
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