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Technical Paper

Sensitivity of Accident Reconstruction Calculations

1998-02-23
980375
A number of simplistic formulae, based on particle dynamics, energy, and momentum methods are routinely employed by accident reconstructionists to calculate vehicle speeds immediately prior to impact. It is almost always the case that scene evidence and other information regarding important variables involved in such equations must either be estimated or can be measured only in an approximate way. ...Example problems illustrate the difficulties faced by accident reconstructionists as they grapple with incomplete and/or estimated values for important variables, and with the inherent sensitivity of some of the calculations to seemingly small variations in variable magnitudes.
Journal Article

Automatic Transmission Gear Ratio Optimization and Monte Carlo Simulation of Fuel Consumption with Parasitic Loss Uncertainty

2015-04-14
2015-01-1145
An enterprise approach for vehicle fleet balancing of fuel consumption objectives based upon selection of automatic transmission gearing strategy is presented. Monte Carlo simulations for the influence of parasitic loss uncertainty for the automatic transmissions selected from the generalized DOE were conducted to determine the range of fuel consumption that might be realized in production. ...Automatic transmission gearing parameter selection was unaffected by the variation introduced by the Monte Carlo simulations, but did show fuel consumption performance to vary upwards of 9 g CO2/km depending on applications and to have a direct impact on powertrain operating parameters.
Technical Paper

Particulate Matter Formation Dynamics as Investigated by Ultra-Accelerated Quantum Chemical Molecular Dynamics Coupled with Canonical Monte Carlo Method

2016-04-05
2016-01-0553
Suppression or reduction of soot emissions is an important goal in the development of automotive engines for environmental and human health purposes. A better understanding at the molecular level of the formation process of soot particles resulting from collision and aggregation of smaller particles made of Polycyclic Aromatic Hydrocarbon (PAH) is needed. In addition to experiments, computational methods are efficient and valuable tools for this purpose. As a first step in our detailed computational chemistry study, we applied Ultra-Accelerated Molecular Dynamics (UAQCMD) and Canonical Monte-Carlo (CMC) methods to investigate the nucleation process. The UA-QCMD can calculate chemical reaction dynamics 107 times faster than conventional first principle molecular dynamics methods, while CMC can calculate equilibrium properties at various temperatures, pressures, and chemical compositions.
Training / Education

Photography for Accident Reconstruction, Product Liability, and Testing

Many technical projects, most vehicle and component testing, and all accident reconstructions, product failure analyses, and other forensic investigations, require photographic documentation. ...This course has been approved by the Accreditation Commission for Traffic Accident Reconstruction (ACTAR) for 20 Continuing Education Units (CEUs). Upon completion of this seminar, accredited reconstructionists should mail a copy of their course certificate and the $5 student CEU fee to ACTAR, PO Box 1493, North Platte, NE 69103.
Technical Paper

Accident Investigation and Reconstruction Mapping with Aerial Photography

1996-02-01
960894
A system has been developed for investigating and reconstructing vehicular accidents using close-range aerial photography. Accident Investigation and Reconstruction Mapping with Aerial Photography, henceforth referred to as AIRMAP, utilizes a tethered blimp and suspended camera in a close-range aerial survey technique. ...Computer-generated graphics of physical evidence, such as vehicles, tire marks, and pedestrians, can be superimposed over the image to produce a plan view photographic map of the accident scene easily understood by a non-technical audience.
Technical Paper

Accident Reconstruction Using Data Retrieval from Crash-Test Video Images

2016-04-05
2016-01-1464
The main source for the estimation of stiffness coefficients to be used in accident reconstruction calculations is a very large database of crash-test related information from NHTSA. ...This methodology allowed to extend the existing database of US cars to European models and to significantly improve the calculation of the dissipated energies associated to the permanent damage caused by accidents.
Technical Paper

The Accuracy of Photogrammetry vs. Hands-on Measurement Techniques used in Accident Reconstruction

2010-04-12
2010-01-0065
A study was conducted to assess the relative accuracy of two measurement techniques commonly used for vehicle measurements in damaged-based accident reconstruction. The traditional technique of hands-on measurement was compared with the use of photogrammetry for measurement of targeted damaged vehicles. ...Hands-on measurements were obtained via two groups of qualified professionals in the field of accident reconstruction, with access to both the vehicles and traditional measuring equipment such as tape measures, crush jig and plumb bobs.
Technical Paper

Reconstruction of 3D Accident Sites Using USGS LiDAR, Aerial Images, and Photogrammetry

2019-04-02
2019-01-0423
The accident reconstruction community has previously relied upon photographs and site visits to recreate a scene. ...This offers many unique benefits to the reconstruction community including: safety, budget, time, and historical preservation. This paper presents a methodology for collecting this data and using it in conjunction with aerial imagery, and camera matching photogrammetry to create 3D computer models of the scene without a site visit.
Technical Paper

Digital Rectification of Reconstruction Photographs

1996-02-01
961049
Computerized photogrammetry as it relates to accident reconstruction is well known and has been documented by a number of researchers. Planar photogrammetry algorithms have been demonstrated to be adequate for a large number of situations involved in reconstruction. ...Planar photogrammetry algorithms have been demonstrated to be adequate for a large number of situations involved in reconstruction. These algorithms all transform individual points in the photographic image plane to a plane associated with the objects of interest. ...The method has specific advantages in analyzing accident scene photos containing skid marks, gouges, and other evidence, without the inconvenience of perspective distortion.
Technical Paper

Analytical Applications of 3-D imaging in Vehicle Accident Studies

1996-02-01
960648
Three dimensional computer animation also has analytical uses that apply to the accident reconstruction field. It can be used to evaluate visibility, timing of complex motions and is helpful in correlating vehicle damage to ground strikes. ...Used in concert with photogrammetry, 3D imaging can be very useful in determining the positions of objects pictured at the accident scene.
Technical Paper

Computer Assisted Single-View Photogrammetry for Accident Scene Documentation

1985-02-25
850067
Accurate documentation of traffic accidents is a prerequisite for accident research as well as traffic jurisdiction. As an important part of accident documentation, stereo-photogrammetry is recognised to be an excellent tool for providing accurate and complete scaled maps of accident scenes. ...ACCURATE AND COMPLETE documentation of traffic accidents is the basis of accident research and analysis. Likewise, it is important for traffic jurisdiction. ...Accordingly, the city police of Zurich introduced stereophotogrammetry as a routine tool for accident documentation purposes as early as 1934 (1)*. Apart from its value for accident jurisdiction, stereophotogrammetry proved to be indispensible for a reliable accident reconstruction and analysis.
Journal Article

Accuracy of SUAS Photogrammetry for Use in Accident Scene Diagramming

2015-04-14
2015-01-1426
Photogrammetry from images captured by terrestrial cameras and manned aircraft has been used for many years to model objects, create scale diagrams and measure distances for use in traffic accident investigation and reconstruction. Due to increasing capability and availability, Unmanned Aircraft Systems (UAS), including small UAS (SUAS), are becoming a valuable, cost effective tool for collecting aerial images for photogrammetric analysis. ...The results show the photogrammetric measurement of an accident scene from SUAS aerial imagery provides measurements with errors well below generally accepted ranges for accident reconstruction....The metric accuracy of scale accident scene diagrams created from SUAS imagery has yet to be compared to conventional measurement methods, such as total station and laser measurement systems, which are widely used by public safety officials and private consultants.
Technical Paper

Band Information Reconstruction from a Single Photo - A Superimposed Method

1996-02-01
960893
To interpret the information on a 2-D image of a 3-D world in order to determine the displacement of the 3-D objects portrayed in the image, this study superimposes the 2-D image with another photo which is taken from the same site and includes some additional objects with well defined dimensions. In this synthetic image, those added objects serve as a datum; mathematical functions are then used to evaluate the true size of any object in the image. In the computerized photogrammetry method proposed in this study, other than the need for an additional photo with known-dimension poles in it and the required adjustment on the direction and distance of this photo to suit for the target one, there is no extra field measurement necessary, nor is any adjustment introduced in the computational process.
Technical Paper

Documenting Scientific Visualizations and Computer Animations Used in Collision Reconstruction Presentations

1998-02-23
980018
Scientific visualizations and computer animations are frequently presented to show the results of simulation models or the opinions of a reconstructionist. In these cases it is important to properly document the graphical images being presented. Proper documentation depends somewhat on the methodologies used to produce the images, but every scientific visualization, computer animation, and computer generated image should be documented sufficiently to allow others to duplicate the images. There are also some basic data that should accompany any computer generated images that will reveal the basis of the motion for all primary objects being depicted. This paper presents some basic definitions and outlines the data that is required to document scientific visualizations and computer animations.
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