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Validation


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Validation


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Validation & Study



Validation and study of Virtual CRASH.

The Virtual CRASH family of simulation products has been used by accident reconstructionists for over a decade. As with any simulation tool, we encourage all of our users to put Virtual CRASH software through their own set of Validation tests; Indeed, in our Trial Version Analyses exercises on the vCRASH Academy page, users are led through a number of exercises designed to illustrate just how reliable Virtual CRASH is for accident reconstruction and physics analyses. We also guide our users through the process of conducting Virtual CRASH analyses to reconstruct RICSAC 1, RICSAC 2, and RICSAC 3 from the crash test validation database Research Input for Computer Simulation of Automobile Collisions (RICSAC), as well as MEA12. Try it for yourself!

Below are a small sample of articles and write-ups based on studies and tests conducted by various accident reconstruction professionals from organizations worldwide.


Abstract: This paper will analyze a pedestrian impact with a 2012 vehicle in a criminal matter. The driver of the vehicle struck the pedestrian before crashing into a chain-link fence and tree. The driver was arrested and charged with vehicular homicide and driving while intoxicated (DWI). The question was: Where was the pedestrian standing when she was struck? The airbag control module was downloaded by the prosecution expert. The speed, steering angle, and longitudinal/ lateral accelerations were recorded for a period of 5 seconds prior to algorithm wake-up as a result of a fence side-swipe and then algorithm enable (AE) for the deployment of the vehicle-side airbags after impacting a tree. The recorded data was input into Virtual Crash and PC-Crash (accident reconstruction software that uses Newton’s laws of motions in analysis). The software allowed the time-distance-speed path of the vehicle to be visualized. The prosecution expert opined that the pedestrian was struck on the sidewalk a short distance from where she came to rest. This author was retained by the defense to determine the pedestrian’s position — either in the roadway or on the sidewalk.

Source: National Academy of Forensic Engineers.

 

 


"Reconstruction of 60º Front-to-Side Staged Collisions with the Virtual CRASH Software Application"

Author: Bob Scurlock, Ph.D., ACTAR (University of Florida, Department of Physics)

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Abstract: Virtual CRASH software is an application primarily used for motor vehicle accident reconstruction. In this article, results from a series of Virtual CRASH simulated vehicle versus vehicle collisions from the Research Input for Computer Simulation of Automobile Collisions (RICSAC) test series are presented; in particular, this article documents simulation results from the RICSAC 1, 2, 6, and 7 oblique 60° front-to-side impact tests.

Submitted to the Accident Reconstruction Journal


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"Traffic Accident Reconstruction and An Approach for Prediction of Fault Rates Using Artificial Neural Networks: A case study in Turkey"

Authors: A. Yilmaz (Cukurova University, Department of Automotive Engineering), C. Aci (Mersin University, Department of Computer Engineering), K. Aydin (Cukurova University, Chair of Department of Automotive Engineering)

Abstract: 

OBJECTIVE: Currently, in Turkey, fault rates in traffic accidents are determined according to initiative of accident experts (sometimes no speed analyses of vehicles, just procession of accident) and there are no specific quantitative instructions on fault rates related to procession of accident in No.2918 Turkish Highway Traffic Act (THTA). The aim of this study is to introduce a scientific and systematic approach for determination of fault rates in most frequent property damage only (PDO) traffic accidents in Turkey.

METHODS: In this study, data (police reports, skid marks, deformation situation of involvements, crush depth, etc.) collected from the most-frequent and controversial accident types (four sample vehicle-vehicle scenarios), which consist of property damage only (PDO), were inserted into a reconstruction software called vCrash. Sample real world scenarios were simulated on the software to generate different deformations on vehicles which also correspond to energy equivalent speed (EES) data just before the crash. These values were used to train Multi-Layer Feedforward Artificial Neural Network (MFANN), Function Fitting Neural Network (FITNET) (a specialized version of MFANN) and Generalized Regression Neural Network (GRNN) models within 10-fold cross-validation to predict fault rates without necessity of any software. The performance of the Artificial Neural Network (ANN) prediction models was evaluated using Mean Square Error (MSE) and multiple correlation coefficient (R).

RESULTS: It was shown that MFANN model performs better results on predicting fault rates (i.e., lower MSE and higher R) than FITNET and GRNN models for accident scenarios 1, 2 and 3 whereas FITNET performed the best for scenario 4. The FITNET model showed the second best results for prediction for the first three scenarios. Since there is no training phase in GRNN, the GRNN model produced results much faster than MFANN and FITNET models. However, GRNN model depicted worst results for prediction. The R values for prediction of fault rates were close to 1 for all folds and scenarios.

CONCLUSIONS: This study focuses on exhibiting new aspect and scientific approach for determining fault rates of involvements in most frequent PDO accidents occurring in Turkey by implying some deficiencies in THTA and without regarding to initiative and/or experience of experts. This study yields judicious decisions to be made especially on forensic investigations and events involving insurance companies. Referring to this approach, injury/fatal and/or pedestrian related accidents may be analyzed as future work by developing new scientific models.

Source: Traffic Injury Prevention, DOI: 10.1080/15389588.2015.1122760


"Simulations of Pedestrian Impact Collisions with Virtual CRASH 3 and Comparisons with IPTM Staged Tests"

Authors: Tony Becker, ACTAR, Mike Reade, CD, and Bob Scurlock, Ph.D., ACTAR (University of Florida, Department of Physics)

Abstract: In this article, we present results from a series of Virtual CRASH-based pedestrian impact simulations. We compare the results of these Virtual CRASH pedestrian impact simulations to data from pedestrian impact collisions staged at the Institute of Police Technology and Management. 

Source: Accident Reconstruction Journal, March/April 2016. Cornell University Library: arXiv:1512.00790. 


"Who was the Driver? How was he Injured? What, if . . . ? Answers Based on Simulation Calculations"

Authors: G. Melegh, Ph.D. (Budapest University of Technology and Economics, Department of Automotive Engineering, Budapest) and G. Vida (Budapest University of Technology and Economics, Department of Automotive Engineering, Budapest)

Abstract: Some basic questions arise during the examination of accidents, such as, who was driving the vehicle, what caused the serious injury suffered by the occupants, what was the effect of wearing or not wearing seat belts. In cases where the recorded marks from the accident scene investigation are not sufficient to answer the question, accident reconstruction can provide the answer.

Source: Presented at the 19th Annual Congress EVU (European Association for Accident Research and Analysis), 2010, Prague.


"Procedure of collision solution with the help of Virtual CRASH software and possibilities of results validation"

Written in Czech

Authors: M. Semela, Ph.D., Engineer (Brno University of Technology, Institute of Forensic Engineering) and Albert Bradac, Ph.D., Engineer (Brno University of Technology, Institute of Forensic Engineering)

Abstract: (translated) This paper focuses on analyzing vehicle collisions using Virtual CRASH software and the influence of each input parameter on the simulation outcomes. We show good agreement between Virtual CRASH and PC-CRASH. A brief description of the Virtual CRASH simulation model is also given.

Source: Journal: Soudní inženýrství, 2007, Volume 18, Issue 3. 2007, CERM, CZ, p. 118-129. ISSN: 1211- 443X


"Research of Impact Parameters for Traffic Accident Analysis in Case of Small Overlap Crash Test: Validation and comparison of impact parameters between real crash data and computer modelling"

Authors: T. Coufal, Ph.D. (Brno University of Technology, Institute of Forensic Engineering) and M. Semela, Ph.D., Engineer (Brno University of Technology, Institute of Forensic Engineering)

Abstract: This article presents an executed frontal small overlap crash test of two vehicles moving at a speed of approximately 43 km/h with the emphasis on the resulting crash parameters for application in traffic accident analyses. The experimentally measured data from the crash test were suitably analyzed and important crash parameters were obtained and applied in impact modelling by a simulation program, which is used to analyse traffic accidents. 

Source: 2nd Annual International Conference on Forensic Science - Criminalistics Research, 2014, year 2, č. 1, s. 1-9. ISSN: 2382- 5642.


"Determination of Selected Crash Parameters in Head-on Vehicle Collision with Rollover"

Authors: T. Coufal, Ph.D. (Brno University of Technology, Institute of Forensic Engineering) and M. Semela, Ph.D., Engineer (Brno University of Technology, Institute of Forensic Engineering)

Abstract: The paper presents complete results of the head-on small overlap crash test of vehicle with driver moving at a speed of approximately 12 m/s against stationary vehicle with post-crash rollover. When a crash does not involve the main crush-zone structures, the occupant compartment is not well protected. The emphasis in the paper was put on determination and presentation of crash parameters for the application in traffic accident analyses and for simulation with the help of software for accident reconstruction. The experimentally measured data from the crash test were analysed and important crash parameters which are necessary for accident reconstruction were obtained. The crash test was specific because of rollover of the impacting vehicle resulting from small overlap. The results have shown that small overlap accident is extremely dangerous for the crew with the possibility of vehicle rollover and occupant head and neck injury. Also in this case, at relative low speed, the driver suffered light neck and head injury in the following days and the longitudinal damage was relatively large. The input parameters for accident reconstruction software as the result of performed crash test were gained.

Source: Promet – Traffic & Transportation, Vol. 28, 2012, No. 1, 2016


"Research of the Influences of Input Parameters on the Result of Vehicles Collision Simulation"

Authors: Professor V. Bogdanovic  (University of Novi Sad, Department of Traffic Engineering, Serbia), N. Milutinovic (Technical College of Applied Studies, Serbia), S. Kostic, and Professor N. Ruskic (University of Novi Sad, Department of Traffic Engineering, Serbia)

Abstract: Vehicle collisions are complex processes which are determined by a large number of different parameters. The development of computer programs for simulation has made the collision analysis and reconstruction procedure easier, as well as the possibility to realize the influences of different parameters on collision processes, which was not possible while using classical methods. The quality of results of vehicle collision simulation and reconstruction is expressed by an error which is determined on the basis of the difference between vehicles stopping positions, which was obtained by the simulation of established vehicles stopping positions in real collisions. Being acquainted with the influence of collision parameters on the simulation error enables the development of more reliable models for automatic optimization of the collision process and reduction of the number of iterations in the procedure of a collision reconstruction. Within the scope of this paper, the analysis and classification of different collision parameters have been carried out. It has been done by the degree of the influence on the error in the simulation process in the software package Virtual CRASH. Varying twenty different collision parameters on the sample of seven crash tests, their influence on the distance, trajectory and angular error has been analysed, and ten parameters with the highest level of influence (centre of gravity position from front axle of vehicle 1, restitution coefficient, collision place in longitudinal direction, collision place in transverse direction, centre of gravity height-vehicle2, centre of gravity height-vehicle1, collision angle, contact plane angle, slowing down the vehicle and vehicle movement direction) have been distinguished.

Source: Promet – Traffic & Transportation, Vol. 24, 2012, No. 3, 243-251


"Reconstruction of an Unusual Road Traffic Accident Using Computer Simulation"

Author: Professor Attila Gonczi (University of Timisoara, Transportation Engineering, Romania)

Abstract: In most of the cases of a road traffic accident reconstruction, the usage of traditional reconstruction methods represents the basic set of tools, but in an ever increasing number of cases, computer simulation is used for control the results or vice-versa. In some cases, traditional methods, based on linear momentum conservation, energy conservation and assessment of deformation of the vehicles or experimental results of crash tests are not suitable because of the highly unusual character of the collision. The paper deals with one case of this type in which the pedestrian was cut in two parts by the hitting car. 

Source: Annals of Faculty Engineering Hunedoara - International Journal of Engineering, 2013, ISSN 1584 - 2665


"Influence of (CG) Position on the Post-Impact vehicle motion"

Master's Thesis

Authors: Ing. M. Kunovsky and  M. Semela, Ph.D., Engineer (Brno University of Technology, Institute of Forensic Engineering)

Abstract: This diploma thesis analyses the influence of the change to the vehicle’s center of gravity on its after-impact movement. The theoretical part of the thesis describes the basic methods which are used in investigation of the transverse, lengthwise and height position of center of gravity or the influence of center of gravity’s vehicle position to its stability and handling. Next part of the thesis deals with basic division of the road accidents and briefly describes the methods used in its analysis. Problematic maneuvers and everyday road traffic situations are stated in this thesis. Chosen situations were simulated in Virtual CRASH and PC crash programmes. Influence of the transverse, lengthwise and height position of center of gravity was investigated in these programmes with regards to the after-impact behaviour of vehicle. The obtained results were evaluated in the final chapter. 

 


"Simulation study of pedestrian impact and throw-distance Validation of the Virtual Crash program"

Authors: G. Melegh, Ph.D. (Budapest University of Technology and Economics, Department of Automotive Engineering, Budapest), G. Vida (Budapest University of Technology and Economics, Department of Automotive Engineering, Budapest), Engineer, D. Sucha, and G. Belobrad

Abstract: Virtual Crash is a new generation program for the simulation of vehicle and pedestrian accidents. It takes ad-
vantage of the latest hardware and software developments that allow for increasingly complex real-time calculations to be performed on a PC. For maximum versatility, Virtual Crash simulation results can be viewed and output in scale plan, 3D perspective view as well as producing numerous diagrams and tables to describe and validate the solution. The accuracy and appropriate operation of the models and calculation algorithms can be evaluated the most properly with validation studies. If we can reproduce the experimental results, then with the use of the program, the modeling of similar events can be done with a similar level of accuracy. 

Source: White paper


"A Pilot Study of an Integrated Accident Research System Based on a Medical and Engineering Data in the Metropolitan Area of Florence"  

Authors: S. Piantini, Ph.D., Engineer (University of Florence, Department of Mechanical and Industrial Technology), D. Grassi (University of Florence, Department of Mechanical and Industrial Technology), M. Mangini, M.D. (University of Florence), M. Pierini, Ph.D. (University of Florence, Department of Mechanical and Industrial Technology), R. Spina, M.D. (Intensive Care Unit of Emergency Department at Careggi University Hospital), and A. Peris, M.D. (Chief of Anesthesia and Intensive Care Unit of Emergency Department at Careggi University Hospital)

Abstract: The Tuscany Trauma Registry (2009‐2010) shows that the preponderance of major trauma due to road accidents occurs in urban areas (33%) and 62% of these involve Powered Two Wheeler (PTW) riders and pillion passengers. So far, the collection of in‐depth real world road accident data has been very limited in Italy and completely absent in the Tuscany region. For this reason a team of physicians and engineers have established a collaborative effort to collect and study all the metropolitan road accidents that result in major trauma. The aim of the project is to create an in‐depth accident database with a special focus on the correlation between the accident dynamics and the injuries. This paper describes the method adopted and a case study representing a typical example of the approach and outcomes. The analysis of 16 cases out the 60 collected during the first year shows some preliminary results. The next step of the project is to consolidate the data gathering by creating a stable structure able to collect data continuously for at least the next 10 years.  

Source: IRCOBI (International Research Council on the Biomechanics of Injury) Conference 2012


"Advanced accident research system based on a medical and engineering data in the metropolitan area of Florence"

Authors: S. Piantini, Ph.D., Engineer (University of Florence, Department of Mechanical and Industrial Technology), D. Grassi (University of Florence, Department of Mechanical and Industrial Technology), M. Mangini, M.D. (University of Florence), M. Pierini, Ph.D. (University of Florence, Department of Mechanical and Industrial Technology), R. Spina, M.D. (Intensive Care Unit of Emergency Department at Careggi University Hospital), and A. Peris, M.D. (Chief of Anesthesia and Intensive Care Unit of Emergency Department at Careggi University Hospital)

Abstract: 

Background: In the metropolitan area of Florence, 62% of major traumas involve powered two wheeler rider and pillion passengers, 10% cyclists, and 7% pedestrians. The urban and extra-urban areas are the most dangerous for the vulnerable road user. In-depth investigations are needed for assessing detailed information on road accidents. This type of study has been very limited in time frame in Italy, and completely absent in the Tuscan region.

Consequently a study called “In-depth Study of road Accident in FlorencE” (In-SAFE) has been initiated.

Methods: A network between the Department of Mechanics and Industrial Technologies (University of Florence) and the Intensive Care Unit of the Emergency Department (Careggi Teaching Hospital, Florence) was created with the aim of collecting information about the road accidents. The data collected includes: on-scene data, data coming from examination of the vehicles, kinematics and dynamic crash data, injuries, treatment, and injury mechanisms. Each injury is codified thorough the AIS score, localized by a three-dimensional human body model based on computer tomography slices, and the main scores are calculated. We then associate each injury with its cause and crash technical parameters. Finally, all the information is collected in the In-SAFE database.

Results: Patient mean age at the time of the accident was 34.6 years, and 80% were males. The ISS mean is 24.2 (SD 8.7) and the NISS mean is 33.6 (SD 10.5). The main road accident configurations are the “car-to-PTW” (25%) and “pedestrian run over” (17,9%). For the former, the main collision configuration is “head-on crash” (57%). Cyclists and PTW riders-and-pillions-passengers suffer serious injuries (AIS3+) mainly to the head and the thorax. The head (56.4%) and the lower extremities (12.7%) are the most frequently injured pedestrian body regions.

Conclusions: The aim of the project is to create an in-depth road accident study with special focus on the correlation between technical parameters and injuries. An in-depth investigation team was setup and is currently active in the metropolitan area of Florence.

Twenty-eight serious road accidents involving twenty-nine ICU patients are studied. PTW users, cyclist and pedestrians are the most frequently involved in metropolitan accidents.

Source: BMC Emerg Med. 2013; 13; 3. PMCID: PMC3606293


"The Effect of Physical Maturation on ATV Head-on Collision Outcome: A Simulation Study"

Authors: M. Hegazy (Southwest Minnesota State University), K. Connor (University of Idaho), K. Crickmore (University of Idaho), and Ahmed Abdel-Rahim (University of Idaho)

 Abstract: The body’s physical response to an ATV head-on collision will depend on the individual's weight, height, and mass distribution. In this study, Virtual Crash 3.0 (vCRASH, Americas, Inc., Newberry, Florida, USA) was used to simulate 2007 Yamaha Raptor ATV (Yamaha Motor Corporation, U.S.A., Cypress, CA) crashing into a wall with child models of different ages operating the vehicle to assess the potential outcome. The child models were males ages 6-19 years. United States 2007-2010 anthropometric reference data were used to identify the 50% percentile weights and heights for the models. Body segment masses were estimated using segment regression equations presented by Jensen and Nassas (1988). Children under 14 consistently hit the handlebars, thus they did not make impact with the wall. Every model that made impact with the wall hit at a linear velocity that may cause a concussion even at the lowest velocity of 24 km/hr when impact is a made with a hard surface. When the model made impact with a softer polyethylene foam pad, the potential for concussion was observed at ATV impact speeds of 48 km/hr and higher. Children under 16 tended to experience an angular velocity at or close to concussion threshold even at the slowest ATV speeds. Again, children 16 years and older did not cross the concussion threshold until the ATV was faster than 48 km/hr. The authors recommend that children under 16 should not operate an adult size ATV and that older children should not drive at speeds faster than 48 km/hr. In addition, helmets and other safety equipment should be worn at all times.

Source: Presented at the Transportation Research Board 96th Annual Meeting


"First Experiment of Real Collisions of Road Vehicles in Serbia" 

Written in Serbian

Authors: I. Bodolo, Ph.D., M. Nenad, Ph.D., T. Bodolo, H. Dejan

Source: Presented at regional Accident Reconstruction Conferences, Zlatibor (2009) and Opatija (2010), Serbia


"Second Experiment of Real Collisions of Road Vehicles in Serbia" 

Written in Serbian

Authors: I. Bodolo, Ph.D., M. Nenad, Ph.D., T. Bodolo, H. Dejan

Source: Presented at regional Accident Reconstruction Conferences, Zlatibor (2009) and Opatija (2010), Serbia


"Third Experiment of Real Collisions of Road Vehicles in Serbia" 

Written in Serbian

Authors: I. Bodolo, Ph.D., M. Nenad, Ph.D., T. Bodolo, H. Dejan

Source: Presented at regional Accident Reconstruction Conferences, Zlatibor (2009) and Opatija (2010), Serbia


"Fourth Experiment of Real Collisions of Road Vehicles in Serbia" 

Written in Serbian

Authors: I. Bodolo, Ph.D., M. Nenad, Ph.D., T. Bodolo, H. Dejan

Source: Presented at regional Accident Reconstruction Conferences, Zlatibor (2009) and Opatija (2010), Serbia


"Validation of Collision Reconstruction Computer Based Method Using Virtual Crash"

Authors: D. Sucha et al

Abstract: The traffic accident reconstruction is realized basically by using two kinds of methods. One of these methods is based on hand calculation” and the other is a computer based method. Both methods are using the principles of mechanics and the fundamental theorems of the collision and there are both valid and appropriate in accident reconstruction. Whatever the adopted method is, it is very important to obtain real results. The accuracy of the results depends on the variety of the parameters utilized, the knowledge and the expert’s experience, the available input data (quantitative and qualitative) and the accuracy of the reconstruction methods. The paper presents the collision reconstruction method based on the simulation using Virtual Crash.

 

Source: Virtual CRASH White Paper


"New Methods in Accident Reconstruction - Virtual Crash"

Written in German

Author: G. Melegh, Ph.D. (Budapest University of Technology and Economics, Department of Automotive Engineering, Budapest)

Abstract: (translated) In this article the Virtual Crash accident reconstruction program presented, its physical background, its operating area.

 

Source: Virtual CRASH White Paper


"Computer Analysis of Car Crashes - Validation of Virtual Crash"

Written in Serbian

Author: Professor M. Vijanic (The Faculty of Transport and Traffic Engineering, Serbia),  N. Milutinovic

Abstract: (translated) This paper presents a computer analysis of seven car crashes. These collisions were reconstructed by using the software package Virtual CRASH. The accuracy of the corresponding operations applied models and calculated in the algorithm can be checked for validation study, ie.
questioning the validity of the program.

Source: Virtual CRASH White Paper


"Impact of usable coefficient of adhesion between tyre and road surface by modern vehicle on its dynamics while driving and braking in the curve"

Author: Vladimír Panáček, Marek Semela Institute of Forensic Engineering, Brno University of Technology, Czech Republic, Vladimír Adamec & Barbora Schüllerová

Abstract: The paper deals in detail with the analysis of driving and braking of the Volvo V40 T5 AWD Cross Country vehicle in the curve with radius 30, 40 and 50 meters laying emphasis on usable coefficient of adhesion values between tyre and road surface in the longitudinal and lateral direction. Individual dynamical driving and braking experiments in the curve were carried out using both modes of the Volvo stability system DSTC. We found out the range of values of coefficient of adhesion in the longitudinal and lateral direction depending on the vehicle speed and curve radius of the road. Experimentally determined values are utilised efficiently for the calculation of limit speed of a modern vehicle in the curve or, for instance, at the forensic reconstruction of a road accident.

Source: Journal Transport


"Traffic Crash Simulation 101"

Author: Gregory Gravesen, ACTAR #592

Source: American Bar Association, Fall 2016 Newsletter 

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Other Videos


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Simulations of other Staged Collisions


Motorcycle Impact Tests

The Virtual CRASH family of physics simulators comes with the unique ability to quickly simulate collisions involving motorcycles. Below we show a series of Virtual CRASH 2.2 simulation tests based on staged experiments presented in SAE 2002-01-0551. 


Real World Motorcycle vs Passenger Car Collision Analysis

Here we see an example of Virtual CRASH 2.2 used to reconstruct real world collision between a station wagon and a motorcycle. The accident was captured on video. Excellent agreement is observed between the video and simulation (courtesy of engineer Sarkozi Tamas of Hungary).


Read World Pedestrian Impact

Here we see an example of Virtual CRASH 2.2 used to reconstruct real world pedestrian impact collision. The accident was captured on video. Excellent agreement is observed between the video and simulation.