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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

A Rule Based System for Accident Reconstruction

1994-03-01
940721
KAR is a prototype rule based Knowledge-based Accident Reconstruction system used at the initial stage of an investigation. The program is capable of calculating vehicle speeds using any combination of the following techniques: skid, roll, overturn, yaw, vault, momentum and energy. ...Motor vehicle accidents are often difficult to resolve since the data is conflicting and of questionable validity. ...Conventional analysis requires a great deal of expertise on the part of the accident investigator. Problems that are conceptual and cannot be reduced to numbers can often be solved using expert system technology.
Technical Paper

The “IMPAC” Computer Program for Accident Reconstruction

1985-02-25
850254
The computer program “IMPAC” (impact Momentum of a Planar Angled Collision) was developed for use in accident reconstruction to study the impact phase of a collision. It may be used for vehicle to vehicle or vehicle to fixed object impacts.
Technical Paper

Accident Reconstruction of Rollovers - A Methodology

2000-03-06
2000-01-0853
The fundamentals of accident reconstruction do still apply, however, and much valuable and insightful test data is available. ...This paper will describe a practical methodology and protocol to assist reconstructionists in reconstructing both on-road and off-road rollover accidents. It will point to previously published rollover studies relevant to the reconstructionist; present a methodology and protocol for documenting and analyzing field data, most specifically accident vehicle damage; and, lastly, it will review various presentation techniques useful for explanation and validation of the reconstructionist ’s conclusions. ...It will point to previously published rollover studies relevant to the reconstructionist; present a methodology and protocol for documenting and analyzing field data, most specifically accident vehicle damage; and, lastly, it will review various presentation techniques useful for explanation and validation of the reconstructionist ’s conclusions.
Technical Paper

The Measured Rolling Resistance of Vehicles for Accident Reconstruction

1998-02-23
980368
Knowledge about vehicle rolling resistance is required to calculate speed loss of accident vehicles during portions of their pre-impact and post-impact trajectory when they are not braking or sliding directly sideways. ...The accuracy of assumed rolling resistance values is most important in accidents with long post-impact roll out distances. Very little hard data are currently available1 and the accident reconstructionist must usually make estimates of drivetrain losses and normal and damaged tire rolling resistance to determine overall vehicle rolling resistance. ...Very little hard data are currently available1 and the accident reconstructionist must usually make estimates of drivetrain losses and normal and damaged tire rolling resistance to determine overall vehicle rolling resistance.
Technical Paper

Tire Models for Vehicle Dynamic Simulation and Accident Reconstruction

2009-04-20
2009-01-0102
This is particularly true for accident reconstruction applications where vehicle motions can occur over wide ranging kinematic wheel conditions. ...This paper includes a discussion of tire force terminology, tire force mechanics, the measurement and modeling of tire force components and combined tire force models currently used in simulation software for the reconstruction of accidents. The paper discusses the difference between the idealized tire force ellipse and an actual tire friction ellipse. ...The example simulations presented in this paper are not intended to reflect the way vehicle dynamic simulation programs are used typically in accident reconstruction.
Technical Paper

Introduction to Traffic Signal Data Loggers and their Application to Accident Reconstruction

2018-04-03
2018-01-0527
Until relatively recently, investigators were limited by the absence of any recording devices within the systems used for traffic signal phasing and timing. Accident reconstruction methods have long relied on the generalized signal phasing and timings programmed for that intersection by the responsible jurisdiction, combined with the vehicle dynamics calculated for the collision sequence in conjunction with witness testimony regarding signal indications and phase changes. ...This paper also presents how to obtain, analyze, and interpret the data logger data and possible applications of such data to accident reconstruction.
Technical Paper

Lane Change Maneuver Modeling for Accident Reconstruction Applications

2002-03-04
2002-01-0817
Lane change maneuvers are often implemented in typical driving applications and more severe swerving maneuvers are occasionally performed in order to avoid motor vehicle collisions. For accident reconstruction purposes, it is necessary to accurately model the vehicle motion and driver response during a lane change maneuver.
Technical Paper

Deceleration Factors on Off-Road Surfaces Applicable for Accident Reconstruction

1995-02-01
950139
This paper presents the results of full scale vehicle testing completed to examine deceleration factors, or friction coefficients, on various off-road and on-road surfaces. Of particular interest is the relationship between vehicle side slip and deceleration rates on soft, off-road, deformable soils. Vehicle testing was conducted at slip angles of 0, 30, 45, 60, and 90 degrees with locked and unlocked wheels. A comparison of the experimental data is made with respect to the theoretical prediction of deceleration being trigonometrically related to slip angle. Results indicate the theoretical prediction as fairly approximate through a portion of the side slip range. As side slip angles approach 90 degrees, actual measured values are higher than predicted.
Technical Paper

Physical Evidence Analysis and Roll Velocity Effects in Rollover Accident Reconstruction

2001-03-05
2001-01-1284
This paper examines the effects of vehicle roll velocity on scrape angle, presents a method to more accurately determine vehicle orientations in rollover accident reconstruction, and briefly discusses the relationship between vehicle revolutions and translational distance. ...Rollover accidents often have a vast amount of information available for determining vehicle and occupant kinetics and kinematics. ...Physical evidence and photographs of the accident scene and vehicle can be used to determine trajectories, distances, velocities and orientations.
Technical Paper

Accident Reconstruction Based on EDR Records - Simulation and Experimental Study

2007-04-16
2007-01-0729
The authors measure and simulate the vehicle motion in situations where typical defensive maneuvers in road traffic are being carried out, namely straight braking, double lane-change (overtaking), and ramp input on the steering wheel. They reproduce the vehicle motion (i.e. velocity, vehicle's C.G. trajectory and yaw angle) by using real records or by the simulated electronic data recorder (EDR) outputs. Thus, they operate in a way that is similar to that employed by forensic experts who analyze the EDR outputs. The employed method provides means of comparing the real or simulated exact values of velocity and of the vehicle's C.G. trajectory to the readings obtained by integrating the EDR outputs simulation. Estimation of the error, produced by the expert employing the EDR outputs, can be made in this way. The results show a possibility of occurrence of significant values of the error for simplified version of the device.
Technical Paper

Possible Errors Occurring During Accident Reconstruction Based on Car “Black Box” Records

2002-03-04
2002-01-0549
The authors simulate the vehicle motion in situations where typical defensive maneuvers in road traffic are being carried out, namely straight braking, singular lane-change and “J-turn”. They reproduce the vehicle motion (i.e. velocity, vehicle's C.G. trajectory and yaw angle) by using the simulated “black box” outputs. Thus, they operate in a way that is similar to that employed by forensic experts who analyze the “black box” outputs. The employed simulation method provides means of comparing the simulated exact values of velocity and of the vehicle's C.G. trajectory to the readings obtained by integrating the “black box” outputs simulation. Estimation of the error produced by the expert employing the “black box” outputs can be made in this way. The body pitch and roll are sources of longitudinal and lateral acceleration recording errors because a gravitational acceleration component for the respective direction is added in simplified version of the device.
Technical Paper

Reconstruction of Rollover Collisions

1989-02-01
890857
The fundamentals of accident reconstruction are applied to rollover collisions. Typical deceleration rates, roll distances, and vehicle damage patterns are discussed.
Technical Paper

Least Squares Collision Reconstruction

1987-02-01
870429
A new method is described and illustrated which solves the planar, two vehicle collision reconstruction problem. The method, called LESCOR (LEast Square Collision Reconstruction), determines the initial velocity components when given: (1) final velocity components, (2) vehicle physical data, (3) damage geometry, (4) collision geometry and (5) the impact coefficients (restitution and friction). ...Five example collision reconstructions are presented based on RICSAC collisions and a field example. The method has provided results which range from good to excellent and is superior to trial and error methods used in the past.
Journal Article

Occupant Trajectory Model using Case-Specific Accident Reconstruction Data for Vehicle Position, Roll, and Yaw

2008-04-14
2008-01-0517
In the fields of accident reconstruction and injury biomechanics, it is often of interest to know details of an occupant's ejection from a vehicle during a rollover. ...In particular, we model the vehicle's longitude, latitude, roll, yaw, and time derivatives thereof, based on data extracted from a particular accident reconstruction. We model the occupant moving in the vehicle and possibly ejected at any time during the rollover. ...Finally, the new model is tailored to the underlying accident reconstruction data, producing a simulation that is based on the uniqueness of a particular rollover event.
Technical Paper

A Method for Accident Reconstruction and Neighborhood Analysis Using an Autonomous Situational Model of Flight and Flight Recorder Data

1999-04-13
1999-01-1434
Available flight recorder data are used to tune the model and reconstruct the accident. Then the model is used for in-depth examination of the accident’s “neighborhood” in autonomous “what-if” simulation experiments under actual and hypothetical conditions. ...Flight accidents with modern aircraft are often a result of complex dynamics of the “pilot (automaton1) - vehicle - operational environment” system. ...An affordable, practically tested technique is proposed to complement current methods of flight accident analysis. A generic situational model of the system behavior and a computer are employed as a virtual test article.
Journal Article

Evaluation of Sliding Mode Observers for Fault Reconstruction on the ADDSAFE Functional Engineering Simulator

2011-10-18
2011-01-2802
The FDI schemes will ultimately be evaluated in the Industrial Benchmarking and Verification FES which uses Monte Carlo methods to generate a statistical distribution and covers all of the desired flight conditions, perturbations and uncertainties in the aircraft parameters under investigation. ...A robust sliding mode reconstruction scheme for the aircraft lateral axis, based on an LPV system representation is presented. ...The sliding mode LPV scheme utilizes LMIs to synthesize the gains of the observer to minimize the effect of uncertainty on the reconstruction signal. The equivalent output error injection signals are obtained from a second order sliding mode structure, which is less susceptible to noise compared to the typical signum function associated with first order sliding.
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