Traffic Accident Reconstruction Research Articles

Forensic medical aspects of traffic accident reconstruction

Injuries and fatalities occur in all forms of transportation. Numerically, road traffic accidents account for the great majority worldwide. Special questions (especially from the forensic medical point of view) are associated with maritime and flight crashes, when bodies are heavily mutilated and severely decomposed (concerning i. e. identification). – Post mortem radiological investigations are of special value (especially body scanning, pm CT, so called virtual autopsy). The pattern of injuries, toxicological findings, and trace evidence vary considerably and the whole scale of forensic medical analyses is required. This concerns for example: Pattern of injury of vehicle occupants, effect of seatbelts, vulnerability of children in vehicles, injuries to motorcyclists, pedal cyclists and pedestrians, cause of death, suicide and homicide, railway injuries and the special dynamics of other motorized transports. Concerning fitness to drive/pilot/navigate/work careful medical (i.e. concerning epilepsy), psychological (concerning psychiatric illness, substance abuse) and toxicological screenings and investigations are required. For example chronic alcoholism and drug dependence have to be evaluated (i.e. by segmented hair analysis). Such drivers are responsible for very severe crashes. According to the German law these persons are banned from driving motorized vehicles.

교통사고 조사 및 재현에서 신형 전자식운행기록계의 신뢰성에 관한 연구

Recently Digital-TachoGraph(DTG) was mounted mandatorily in commercial vehicles(Taxi, Bus, etc.). DTG records accurate and detailed information of the running state of vehicles related to traffic accident, such as Time, Distance, Velocity, RPM, Brake ON/OFF, GPS, Azimuth, Acceleration. Thus those standardized data can play an important role in traffic accident investigation and reconstruction. To develope the accurate and objective method using the DTG data for the reconstruction of traffic accident, we had conducted several tests such as driving test, high speed circuit test, braking test, slalom test at Korea Automobile Testing & Research Institute(KATRI), and collision test at Korea Automobile insurance repair Research and Training center(KART) with the vehicle equipped with several DTG. Development of the program which enables the reading and analysis of the DTG data was followed. In the experiments, we have found velocity error, RPM error, brake signal error and azimuth error in several products, and also non-continuous event data. The cause of these errors was deduced to be related to the correction factor, the durability of electronic parts and the algorithm.

Study on the Application of Rigid Body Dynamics in the Traffic Accident Reconstruction

The analysis of road vehicle collision accidents reconstruction is a hot automotive passive safety subject. When reconstruct the vehicle collision accidents , start from the final position of the vehicle, and build the back projections by using the kinematic and dynamic models, according to the relevant theory, experimental data. namely: the after collision stage - Collision stage - pre-crash phase to reproduce the actual situation of the entire accident process in time and space. Thus the technical state of vehicle accidents before the collision can be known, and the causes of the accidents can be further analyzed. In this paper, some aspects related to rigid body kinematics and rigid body dynamics will be studied.

A Method for Reconstructing Vehicle - Vehicle Impact Accidents Based on Pc-Crash

To reconstruct accident succinctly and scientifically, four steps of vehicle-vehicle impact accident reconstruction based on Pc-Crash were discussed, including accident scene reconstruction, vehicle modeling, accident reconstruction, result analysis and verification. Three accident scene reconstruction methods were proposed. Key attention was paid to methods which can reduce difficulties of accident reconstruction, such as drive model, equivalent energy speed (EES) database and collision optimizer. Finally, a case study was conducted, which confirmed that the proposed four steps can simplify vehicle-vehicle accident reconstruction while maintaining satisfying objectivity and reliability. This paper can contribute to the better application of Pc-Crash to traffic accident reconstruction.

차량속도와 도로의 종단경사 변화에 따른 차량거동 특성

Abstract When a vehicle is running on the road, the surface conditions and environment of road by reason of insufficient road design standards is so greatly that have an effect on drivers. In particular, the road design of the past is conducted empirical and ideal judgment, but recently, the new technical development is attempted that three and four dimensional parameters is reconsidering and adjusting at the same time. In this study, we analyzed the vehicle behavior characteristics according to the change of driving speed and vertical grades on braking at the peak point of the frozen road by using a PC-crash program for traffic accident reconstruction. As a result, we were conformed the fact that the friction coefficient of road surface and the vehicle speed is affected by vehicle behavior characteristics for intersection vertical grades and were showed the feasibility of verification through a simulation in order to solve the problem of road design in advance. Key Words : Intersection, Vertical Grades, PC-crash, Load Alignment

The Accuracy Analysis of Measurement Tools for Traffic Accident Investigation

The objective of traffic accident reconstruction is to recreate the event, which is necessary for analyzing the collision dynamics that is used as evidence in court cases. Traffic accident reconstruction and a demonstration of the event require precise data pertaining to scene measurement. However, there are differences between the individual measuring tools and methods related to traffic accident investigation, just as there are differences between the extent of their use and measurement accuracy. The most commonly applied method is the measuring tape, followed by measurements with total stations and laser rangefinders, while photogrammetry is also becoming increasingly important. The advantages and disadvantages of individual tools and methods affect the required number of investigators, portability, measurement range, applicability depending on the amount of light and weather conditions, on the possibility of remote measurement, on data collection time, on the scope, on the option to later process, the collected data and above all on the accuracy of all gathered data. The latter is crucial for proving the guilt or innocence of traffic accident participants at court, as inaccurate data can lead to an unjust sentence. Measurement accuracy using the above mentioned tools and methods also varies depending on which ones are used, as well as on other factors.

Application of cross-ratio in traffic accident reconstruction

Nowadays, video recording devices such as CCTV, digital cameras, mobile phones and car video recorders are ubiquitous. It becomes more and more frequent that traffic accident scenarios are captured by such video recording devices in one form or another. The present study focuses on the direct extraction of vehicle speeds from video footages by cross-ratio, a well known invariant under specific conditions in projective geometry. The minimum requirements for an accurate and direct determination of vehicle speed by cross-ratio are 2 image frames of the video footage containing the subject vehicle which by and large moves along a straight path from one frame to the other and the time lapsed between the 2 image frames are known. With the aid of a calibrated Doppler radar, a control study has been carried out to validate the method and determine the baseline uncertainty. The validated method has been applied to a small number of real world cases and the results are promising. Experimental results indicate that it is possible to extend its application in speed determination by a car camera.

A Google map-based traffic accident reconstruction system

Both traffic accident reconstruction and responsibility confirmation of traffic accident depend on crash scene diagramming and crash simulation. However, mistakenly recorded road geometry of the crash scene usually causes misunderstandings in the crash scene diagramming and thus the result of accident reconstruction is untrustworthy. Research has thus been continuously done to solve the problem. This study proposed a Google Map-based accident reconstruction system integrating functions of crash scene diagrammingand crash simulation. The modulus of crash scene diagramming includes positioning of accident location, Google satellite map and Google Sketch Up to accurately present road geometry and accident vehicle position information. The modulus of crash simulation refers to the vehicle dynamic differential equations generated using the Newton-Euler formulation, and enhances with the calculation of momentum conservation in the collision to predict the vehicle dynamics after collision. The system developed in this study was validated using a real case. The results showed that a crash scene diagramming correctly drawn on the Google satellite map was an ideal platform to present the crush simulation, and help people understand or make a judgment for accident authentication. Key words: Accident reconstruction, Google map, crash scene diagramming, crash simulation.

Probabilistic Inverse Simulation and Its Application in Vehicle Accident Reconstruction

Inverse simulation is an inverse process of direct simulation. It determines unknown input variables of the direct simulation for a given set of simulation output variables. Uncertainties usually exist, making it difficult to solve inverse simulation problems. The objective of this research is to account for uncertainties in inverse simulation in order to produce high confidence in simulation results. The major approach is the use of the maximum probability density function (PDF), which determines not only unknown deterministic input variables but also the realizations of random input variables. Both types of variables are solved on the condition that the joint probability density of all the random variables is maximum. The proposed methodology is applied to a traffic accident reconstruction problem where the simulation output (accident consequences) is known and the simulation input (velocities of the vehicle at the beginning of crash) is sought.

Recognition and Extraction of Debris Parameters in Traffic Accident Picture

In order to obtain characteristic parameters of the debris from accident pictures for traffic accident reconstruction, MATLAB image processing technology was applied to deal with accident pictures such as grayscale transformation, binarization, noise reduction and segmentation. According to the proportional relationship obtained by camera calibration between pixel and the actual size, the diameter of sphere debris, the length and width of rectangular debris were achieved. The error calculated by comparing extraction parameters of accident picture with real size is within 5%.

Analysis of the Influence of Vehicle Dynamic Parameters on Tire Marks

ABSTRACT Tire marks play a central role in the reconstruction of traffic accidents, since they can provide valuable information about the vehicle's trajectory, initial speed, or the steering and braking input of the driver. The research project described in this paper focuses on the analysis of tire marks under controlled conditions using a monowheel setup to enable a selective variation of different vehicle dynamic parameters without mutual influence. The long-term goal is to find a model for the development of tire marks to predict the influence of specific vehicle dynamic parameters on the generation of tire marks. This model may be applied in accident reconstruction tools. A literature review has been performed to find evidence for the development of tire marks and to identify relevant parameters for their generation. Currently, no explicit physical or mathematical model showing the influence of tire forces or slip on the generation of tire marks is available. In the literature, it is often assumed that tire marks occur at the limit of traction. A physically motivated formula has been developed to calculate the friction force within the contact patch as a function of the tire forces, the longitudinal slip, and the side slip angle. The main hypothesis deduced from this formula is that the intensity of a tire mark depends on the magnitude of this friction force independent of the varying parameter. To verify this hypothesis, experiments have been conducted with variations in longitudinal slip, side slip angle, and tire type. First results agree with the model, showing a correlation between the intensity of tire marks and friction force, depending on the tribological and optical tire and road properties. This correlation is introduced as tire-marking sensitivity.

매개변수에 따른 커브 길에서 차량 선회특성에 관한 연구

Abstract Entry speed of the vehicle and lateral acceleration acting on the vehicle, roll-angle associated with the overthrow, and then the structure of the road, the friction of road surface are important factors in turning on the curved road. In this study, we analyzed the state change of the vehicle causing entry speed of the vehicle and superelevation of the road, the friction coefficient by using a PC-crash Program for traffic accident reconstruction. As a result, when vehicle is turning the curved road, we could ascertain that the structure of the road and state of the road surface are a major factor about the set up of limited speed. Key Words : Entry Speed, Lateral Acceleration, Roll-Angle, Friction Coefficient, Superelevation * 정회원, 가천대학교 기계· 자동차공학과 ** 정회원, 가천대학교 기계· 자동차공학과접수일자 2012년 8월 20일, 수정완료 2013년 2월 2일게재확정일자 2013년 4월 12일Received: 20 August 2012 / Revised: 2 February 2013 /Accepted: 12 April 2013 ** Corresponding Author: jkyoon@gachon.ac.krDept. of Mechanical and Automotive Engineering, Gachon University, Korea

Forensic Engineering Analysis Of Acceleration Of Cars Vans Light Trucks And Suv’s

Often, Particularly In The Reconstruction And Analysis Of Traffic Accidents At Or Within Intersections, The Time For One Or More Of The Vehicles To Reach The Point Of Impact And Their Speed At Impact Are Im-Portant Factors. In Cases Where Vehicles Enter The Intersection From A Stopped Condition, Such Times And Speeds Are Typically Obtained By Assigning To The Vehicle Of Interest An Average Acceleration And Comput-Ing The Time To Travel To Impact And Speed At Impact By Using Elementary Physics. However, Justification Of An Assumed Acceleration Can Become A Critical Issue At Time Of Trial Since Rarely Is The Reconstructionist Able To Support The Reasonableness Of His Estimate For Acceleration And/Or Its Applicability To The Involved Accident. This Paper Provides Means For Estimating Time-To-Impact And Speed-At-Impact For Passenger Cars, Vans, Light Trucks, And Suvs Starting From A Stopped Condition To Impact, Both For Vehicles Traveling Straight And Turning. The Equations And Procedures Developed Are Based On Empirical Acceleration Data From Multiple Sources Which Show That The Acceleration Of Such Vehicles, When Starting From A Stopped Condition, First Increases To A Peak Value Then Falls Off As A Function Of Velocity.

Reconstruction of road accidents where pedestrians are involved

This article describes the investigation methodology used in road crashes in the Department of Investigation and Traffic Accident Reconstruction (DIRAT) of the Traffic School of the Spanish Guardia Civil. It has deliberately chosen to run over pedestrians for the exhibition of this methodology, given the almost unanimous scientific opinion considers this type one of the most difficult to investigate. It begins with a theoretical exposition on the subject, which sets out briefly the embodiment of Ocular Technical Inspection; the data must be obtained from the same, and the need to obtain additional information of different sources about highway, vehicles, drivers, victims and witnesses. Later, we apply software tools, specifically PC—Crash, to verify the analysis and results obtained by the analytical and sequential reconstruction of the pedestrian collision. This process has just allowing for reviewing and identifying the factors, conditions and causes that motivated the road crash. As a complement, it is shown as theoretical methodology is applied to a real case of pedestrian collision investigated and solved by the DIRAT. Finally, the conclusions reached along this work are enumerated and the lines of future work are drawn.

An Attempt to Attain New Information in Reconstruction of Road Traffic Accidents Applying Digital Image Processing

Court expertise dealing with the reconstruction of road traffic accidents often have to take into account the possibility that an accident could have been a set-up. Such suspicions can be eliminated only by considering all the evidence material from the accident scene. In case of photographic material experts come across the missing material, bad lighting, lack of contrast, different angle perspectives, blurring, omitting important details, etc. Therefore, different methods in forensics image processing have been developed. Most of these methods are primarily used in the processing of different types of photographic material, but some can be applied in the field of road accidents analyses. This paper shows the implementation of digital image processing methods used for processing of remotely sensed imagery. Even though the photographic evidence is incomplete, it is possible to determine the position and dispersion of different materials. This gives the experts additional information that can help in understanding with relatively high probability if the collision between vehicles occured at all and if it did, where. The paper consists of the presentation and description of methods used for digital image processing in a real case study while reconstructing the road accident. KEY WORDS: road traffic accidents, forensics, induced traffic accidents, image classification, digital image processing

An Investigation on Speedometer Pointer Residual-Value of Crashing Vehicle and its Application in Accident Reconstruction

According to the experience of traffic accident investigation over the years, the pointer of some crashed vehicles’ speedometer will stay in one place because of collision spread or heavily vibration, which may indicate the vehicle collision speed. However, the correlation between the residual speed value and actual vehicle collision speed still remains to be examined. For the practical needs of traffic accident reconstruction, this research work is carried out. Based on the principles of traditional speedometers, vehicle impact mechanics and failure mechanism, the damage and failure mode of speedometer in collision are studied. Through the statistics of 15 real traffic accident cases, the features and law about the pointer information of damaged speedometers are obtained initially. As an example, one of these cases is analyzed and calculated to verify the assumption. The availability of the mark information on the indicated place of speedometer after accidents (i.e. the correlation between the speed value of pointers and actual vehicle collision speed) is discussed, which can provide effective means and references for accident reconstruction and vehicle speed identification.

Special Considerations for TDOA Application to the Reconstruction of Traffic Accidents

Investigation at scene is the key issue to Scene Traffic Accident Reconstruction(TAR). Although the photogrammetry technique is widely applied in China due to its convenience and lower cost, it can only provide the final state of the traffic accidents. In this paper, a novel method based on the time difference of arrival (TDOA) technique was proposed to monitor the location of the vehicles passing the accident-prone section on the highway. The methodology of application of TDOA to the Traffic accident scene investigation was proposed, and the arrangement of sensors on the accident-prone sections of the selected freeway is discussed. Based on the coordinates collected by TDOA receivers, real-time position of the each vehicle moving on the accident-prone section could be extracted respectively and when the accidents happen, the traces of the vehicles involved would be obtained. It could be concluded that this method is important supplement to photogrammetry technique during accident scene investigation and could make the forensic judgment of accident responsibility more accurate.

Virtopsy—noninvasive detection of occult bone lesions in postmortem MRI: additional information for traffic accident reconstruction

In traffic accidents with pedestrians, cyclists or motorcyclists, patterned impact injuries as well as marks on clothes can be matched to the injury-causing vehicle structure in order to reconstruct the accident and identify the vehicle which has hit the person. Therefore, the differentiation of the primary impact injuries from other injuries is of great importance. Impact injuries can be identified on the external injuries of the skin, the injured subcutaneous and fat tissue, as well as the fractured bones. Another sign of impact is a bone bruise. The bone bruise, or occult bone lesion, means a bleeding in the subcortical bone marrow, which is presumed to be the result of micro-fractures of the medullar trabeculae. The aim of this study was to prove that bleeding in the subcortical bone marrow of the deceased can be detected using the postmortem noninvasive magnetic resonance imaging. This is demonstrated in five accident cases, four involving pedestrians and one a cyclist, where bone bruises were detected in different bones as a sign of impact occurring in the same location as the external and soft tissue impact injuries.

Geometry features measurement of traffic accident for reconstruction based on close-range photogrammetry

This paper studies the feasibility of investigating a traffic accident and offering initial data for traffic accident reconstruction (TAR) using a photogrammetric technique. Compared with the conventional roller tape applied by the traffic police of Shanghai Municipal Bureau of Public Security in 142 traffic cases, photogrammetry is proven to be a time saving and cost effective method for accident investigation. The 2D photogrammetry method and the trajectory analysis accident reconstruction technique are applied to actual traffic accidents. With the assistance of a Portable-Control System as the reference system, the 3D photogrammetry method can be used in a vehicle deformation survey. The measurement results obtained in accordance with the CRASH survey criteria for vehicle deformation can be adopted as initial information for the damage analysis reconstruction technique. It appears that photogrammetry has greater potential for application to traffic accident investigation and reconstruction.

Analysis of Traffic Accident Reconstruction Uncertainty

AbstractThere are many uncertain factors in road traffic accident. It is necessary to consider the uncertainty influence of these factors by random theory to improve the analysis veracity. In order to improve the precision and reliability of traffic accident analysis and reconstruction, random theory and the probabilistic perturbation method were introduced in this work for the uncertainty analysis of traffic accident because of the existing of uncertainty factors universally. The confidence interval and confidence of parameters were obtained expediently by the uncertainty analysis, and the precision of traffic accident analysis or reconstruction was improved. A typical vehicle-pedestrian accident was investigated by the method proposed, and the calculated result is contrasted with Monte Carlo simulation method, which proves that the method adopted in the paper is accurate and effective.