Your Selections

Accident reconstruction
Show Only

Collections

File Formats

Content Types

Dates

Sectors

Topics

Authors

Publishers

Affiliations

Committees

Events

 

Advanced Applications of Heavy Vehicle EDR Data

  • Professional Development
  • C1901
Published 2019-06-28
This class will provide the student with the skills, knowledge, and abilities to interpret, analyze and apply Heavy Vehicle Event Data Recorder (HVEDR) data in real world applications. This course has been designed to build on the concepts presented in the SAE course Accessing and Interpreting Heavy Vehicle Event Data Recorders (ID# C1022). Advanced topics will include associating HVEDR data with collision events through timestamps, odometer logs, and data signatures, validating HVEDR speed data using specified vehicle parameters, performing time and distance analyses using HVEDR data, and correlating HVEDR data to physical evidence from the vehicle and roadway. These higher-level techniques and applications are intended to increase student understanding of applying HVEDR data to a crash reconstruction analysis.Upon completion of this course, participants will be able to: Associate HVEDR information to real world crashes based on vehicle configurations, parameters, and incident specific data using timestamps, odometers, logs, and physical evidenceEvaluate and compare multiple data sets from different vehicle systems (either OEM or aftermarket)Establish area of impact and vehicle approach considerations based on HVEDR data and…
 

Basic Science and Art of Aircraft Wreckage Reconstruction

Knutson Aviation Services-Donald F. Knutson
  • Book
  • R-480
Published 2019-06-25 by SAE International in United States

Basic Science and Art of Aircraft Wreckage Reconstruction is a unique title which addresses important aspects of investigating crashes, who does this kind of work, and how a healthy attitude and open mind are required to properly perform investigations. It also discusses what to expect from the on-scene part of the investigation, and the fundamental approaches to common types of wreckage reconstruction.

Annotation icon
 

Lateral and Tangential Accelerations of Left Turning Vehicles from Naturalistic Observations

Kineticorp LLC-Neal Carter, Steven Beier, Rheana Cordero
Published 2019-04-02 by SAE International in United States
When reconstructing collisions involving left turning vehicles at intersections, accident reconstructionists are often required to determine the relative timing and spacing between two vehicles involved in such a collision. This time-space analysis frequently involves determining or prescribing a path and acceleration profile for the left turning vehicle. Although numerous studies have examined the straight-line acceleration of vehicles, only two studies have presented the tangential and lateral acceleration of left turning vehicles. This paper expands on the results of those limited studies and presents a methodology to automatically detect and track vehicles in a video file. The authors made observations of left turning vehicles at three intersections. Each intersection incorporated permissive green turn phases for left turning vehicles. The authors recorded video of left turning vehicles at each intersection from a small unmanned aerial system (sUAS), and that video was analyzed with a convolutional neural network designed to detect vehicles. The detected vehicles were then tracked over time and the results were analyzed. A total of 86 left turning vehicles were analyzed. In 23 of the…
Datasets icon
Annotation icon
 

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

Kineticorp LLC-Toby Terpstra, Jordan Dickinson, Alireza Hashemian, Stephen Fenton
Published 2019-04-02 by SAE International in United States
The accident reconstruction community has previously relied upon photographs and site visits to recreate a scene. This method is difficult in instances where the site has changed or is not accessible. In 2017 the United States Geological Survey (USGS) released historical 3D point clouds (LiDAR) allowing for access to digital 3D data without visiting the site. 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. To determine accuracies achievable using this method, evidence locations solved for using only USGS LiDAR, aerial images and scene photographs (representative of emergency personnel photographs) were compared with known locations documented using total station survey equipment and ground-based 3D laser scanning. The data collected from three different site locations was analyzed, and camera matching photogrammetry was performed independently by 5 different individuals to locate evidence. On average, the resulting evidence…
Annotation icon
 

Accuracy Assessment of Three-Dimensional Site Features Generated with Aid of Photogrammetric Epipolar Lines in PhotoModeler and Using Minimal sUAS Imagery

Inverse Scientific, LLC-Andrea Long
Ohio State University-Scott Allen Noll
Published 2019-04-02 by SAE International in United States
Photogrammetry is widely used in the accident reconstruction community to extract three-dimensional information from photographs. This article extends a prior study conducted by the authors, whereby model accuracy was assessed for a technique that exploited vehicle edges and epipolar line projections to construct 3D vehicle models, by examining 3D roadway and site features. To do so, artificial images were generated using an ideal computer-generated camera within a computer-assisted drawing environment to allow for a known reference model to compare with results produced using photogrammetry. A systematic study was undertaken by modeling the curvature, elevation, and super-elevation of a roadway and associated markings, sidewalks, and buildings, either by relying on discrete points or utilizing epipolar lines. The models were assessed for accuracy, and the sensitivity of the accuracy to camera elevation was considered. Subsequently, the photogrammetric procedures were applied to actual sites, and the results were compared with 3D total station and scanner measurements. A further goal of this study was to evaluate modeling accuracy for cases in which a minimal number of sUAS images were…
Datasets icon
Annotation icon
 

Probability of Frontal Airbag Deployment in Bumper-Bumper and Underride Collisions

National Biomechanics Institute-Felix Lee, Caitlin H. McCleery, Christina Ngo, Manon Limousis-Gayda, Rami Hashish
Published 2019-04-02 by SAE International in United States
Airbag deployment thresholds can be a useful metric of collision severity in accident reconstruction applications. The National Automotive Sampling System (NASS) has provided a publicly-available database of real-world motor vehicle collisions, including more than 10,000 event data recorder (EDR) reports retrieved from airbag control modules. These reports typically indicate the airbag deployment status and the corresponding Delta-V of each recorded event. A prior study analyzing crash data in the NASS database demonstrated the airbag deployment threshold varies between vehicle manufacturers and over time. However, the analysis was limited to Ford and GM vehicles due to insufficient data. This paper expands on the prior study of frontal airbag deployment thresholds by analyzing newer years of NASS EDR data (4,000 additional reports). We found that the Delta-V threshold for a 50% probability of deployment event is higher for Toyota than for GM and Ford vehicles. Moreover, SUVs and pickup trucks had higher deployment thresholds than sedans. An increase in Delta-V thresholds was observed for more recent vehicle model years. A higher Delta-V is required for frontal airbag…
Datasets icon
Annotation icon
 

Uncertainty in Radius Determined by Multi-Point Curve Fits for Use in the Critical Curve Speed Formula

MEA Forensic Engineers & Scientists-Bradley Heinrichs, Troy Mithrush
Published 2019-04-02 by SAE International in United States
The critical curve speed formula used for estimating vehicle speed from yaw marks depends on the tire-to-road friction and the mark’s radius of curvature. This paper quantifies uncertainty in the radius when it is determined by fitting a circular arc to three or more points. A Monte Carlo analysis was used to generate points on a circular arc given three parameters: number of points n, arc angle θ, and point measurement error σ. For each iteration, circular fits were performed using three techniques. The results show that uncertainty in radius is reduced for increasing arc length, decreasing point measurement error, and increasing number of points used in the curve fit. Radius uncertainty is linear if the ratio of the standard deviation in point measurement error (σ) to the curve’s middle ordinate (m) is less than 0.1. The ratio σ/m should be less than 0.018 for a radius found using a 3-point circular fit to be within 5% of the actual value 95% of the time. Increasing the number of points used for the fit reduces…
Datasets icon
Annotation icon
 

Two Phase Heavy Truck Acceleration Model

Kineticorp LLC-David Danaher, Sean McDonough, Drew Donaldson
Published 2019-04-02 by SAE International in United States
There have been several papers published over the past 25 years regarding the acceleration of heavy trucks, including different loading conditions, drivetrain configurations, and driving techniques. The papers provide a large data set that measures the speed, distance, and time of the vehicles during acceleration testing and present the data in tabular or graphical formats. Although the data as presented can be useful, it can be challenging to pore over all the data to determine the correct set for a specific application in accident reconstruction. As of this paper’s date of publication, there are approximately eight relevant papers with a total of 268 acceleration tests performed, spanning many years. This paper reviews all the available published literature and summarizes the relevant data in a comprehensive list of accelerations for different heavy truck configurations, which provides a valuable resource to the accident reconstruction field.
Annotation icon
 

Validation of the Cycles Engine for Creation of Physically Correct Lighting Models

JS Forensic Consulting, LLC-Jeffrey Suway
Momenta, LLC-Anthony Dominic Cornetto
Published 2019-04-02 by SAE International in United States
Vision is the primary sense used to navigate through this world when driving, walking, biking, or performing most tasks. and thus visibility is a critical concern in the design of roadways, pathways, vehicles, buildings, etc. and the investigation of accidents. In order to assess visibility, the accident scene can be documented under similar conditions. Geometric and photometric measurements can be taken for later analysis. Calibrated photographs or video of a recreated scene can be captured to illustrate the visibility at a later time. This process can often require significant coordination of the physical features at the scene. It can be difficult to precisely control the motion and timing of moving features such as pedestrians and vehicles. The result is fixed in that you capture specific scenarios with specific conditions with the selected field of view and perspective of the cameras used. Alternatively, three-dimensional computer modeling and physically-based rendering (PBR) can be used to recreate an accident scene geometry and lighting conditions. PBR is a rendering method to create synthetic images and video by accurately simulating…
Annotation icon
 

Speeds of Child Cyclists

Exponent Inc.-Caroline Crump, Young Bui
Published 2019-04-02 by SAE International in United States
Many published studies have characterized walking and running speeds of young children. However, there is a paucity of data on the cycling speeds of very young children (4 to 5 years old). The purpose of this study was to obtain an estimate of cycling speed for boys and girls both who are learning to ride bicycles (i.e., younger children who still ride with training wheels) and who have already learned to ride bicycles (i.e., slightly older children who no longer use training wheels). A sample of 32 child riders (17 boys, 15 girls; 17 four-year-olds who still ride with training wheels, 15 five-year-olds who do not) were asked to ride a short pre-defined distance at their usual speed when riding, and again at their highest speed. We found that while age and experience can differentiate riders, there were only small differences between boys’ and girls’ speeds in either age group. These descriptive results can be used in various applications from traffic engineering to accident reconstruction.
Datasets icon
Annotation icon