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Viewing 1 to 30 of 3484
2017-03-28
Technical Paper
2017-01-1411
Gary A. Davis
For at least 15 years it has been recognized that pre-crash data captured by event data recorders (EDR) might help illuminate the actions taken by drivers prior to a crash. In left-turning crashes where pre-crash data are available from both vehicles it should be possible to estimate features such as the location and speed of the opposing vehicle at the time of turn initiation and the reaction time of the opposing driver. Difficulties arise however from measurement errors in pre-crash speed data and because the EDR data from the two vehicles are not synchronized; the resulting uncertainties should be accounted for. This paper describes a method for accomplishing this using Markov Chain Monte Carlo computation. First, planar impact methods are used to estimate the speeds at impact of the involved vehicles. Next, the impact speeds and pre-crash EDR data are used to reconstruct the vehicles’ trajectories during the approximately 5 seconds preceding the crash.
2017-03-28
Technical Paper
2017-01-1307
Puneet Bahri, Praveen Balaj Balakrishnan, Ravi Purnoo Munuswamy
The change in thickness and work hardening that arise during the forming process are generally ignored in quasi-static analysis for Seat belt pull when performed on vehicle body. However, it is a well-known effect that the physical properties of steel can alter significantly during the manufacturing process. This comprises an increase of material stiffness due to plastic deformation as well as gage changes. Generally, these changes are of very local nature and in the past, crash software tools didn't support the introduction of these local effects, so that they couldn't be taken into account. In the meanwhile LS-DYNA has the capability to import information provided by stamping tools. Thereby a very important part of the material properties can be introduced into the quasi-static simulation models, leading to a significantly increased correlation to test results.
2017-03-28
Technical Paper
2017-01-1447
Pardeep K. Jindal, Rahul Makwana, Djamal Midoun, Edward Abramoski, Matthew Makowski, Ravi Kodwani
In 2012, the Insurance Institute for Highway Safety (IIHS) added a new frontal impact test to its vehicle crashworthiness rating protocol, often referred to as the “Small Overlap Rigid Barrier” (SORB) test. The objective of the present numerical study was to develop an innovative driver knee airbag (KAB) to address anthropomorphic test device (ATD) Knee-Thigh-Hip (KTH) response relative to the IIHS’s rating system of “Good, Acceptable, Marginal or Poor”. The approach used in this study utilized advanced morphing techniques in a sophisticated finite element (FE) model of a vehicle with an ATD and a restraint system. The key challenge in the study was to manage vehicle deformation with minimal changes to the KAB inflator and volume. Several KAB designs in terms of (width, height and depth) were simulated until a design resulted in changing the KTH rating from “Poor” to “Good”.
2017-03-28
Technical Paper
2017-01-1456
Shailesh Pawar, Sandeep Sharma, Manoj sharma
The heavy and light commercial vehicles are equipped with protection devices to enhance the safety of occupants in small vehicles in the event of under run and to reduce the degree of intrusions. These protection devices are SUPD (side under run protection devices), RUPD (rear under run protection devices), FUPD (front under run protection devices). Any passenger vehicles can impact with the heavy vehicles either from rear, front or side and meet the sever accident. During these types of impacts, there is a possibility that the passenger vehicle will go under the front, rear or side part of the truck and bus and cause serious injuries to the occupants. Side underrun protection device is one of the important system implemented in Vehicles as a regulatory requirement (as per IS 14682: 1999) for passive safety of N2 and N3 category vehicles.
2017-03-28
Technical Paper
2017-01-1457
Jingwen Hu, Nichole Ritchie Orton, Rebekah Gruber, Ryan Hoover, Kevin Tribbett, Jonathan Rupp, Dave Clark, Risa Scherer, Matthew Reed
Among all the vehicle rollover test procedures (SAE J2114 dolly, curb-trip, corkscrew ramp, ditch/embankment, soil trip, etc.), the dolly rollover test is the most widely used. However, it requires the test vehicle to be seated on a dolly with a 23° initial angle, which prevents a vehicle over 5,000 kg to be tested, and repeatability is often a concern. In the current study, we developed and implemented a new dynamic rollover test methodology focused on evaluating crashworthiness and occupant protection that does not require an initial vehicle angle. To do that, a custom cart was designed to carry the test vehicle laterally down a track. The cart incorporates two ramps under the testing vehicle’s trailing-side tires. In a test, the cart with the vehicle travels at the desired test speed and is stopped by a track-mounted curb. The cart stopping pulse is modulated using two honeycomb blocks.
2017-03-28
Technical Paper
2017-01-1471
Xiao Luo, Wenjing Du, Hao Li, Peiyu LI, Chunsheng Ma, Shucai Xu, Jinhuan Zhang
Occupant restraint systems are developed based on some baseline experiments, while these experiments can only represent a small part of various accidents, so the current design of occupant restraint systems cannot provide the optimum protection effects for occupants during the majority of accidents. This study presents an approach to predict occupant injury before the collision happens, so that the occupant restraint system can be adjusted to the optimum parameters aiming at the imminent vehicle-to-vehicle frontal crash. The approach in this study takes advantages of the information from pre-crash systems, such as the time to collision, the relative velocity, the frontal overlap of the ego vehicle during the collision, the size of the vehicle in the front and so on. The information acquired and the basic crash test results can be integrated to predict a simplified crash pulse, and the injury of the occupant in the ego vehicle can thus be predicted using this crash pulse.
2017-03-28
Technical Paper
2017-01-1472
Niels Pasligh, Robert Schilling, Marian Bulla
Rivets, especially self-piercing rivets (SPR), are one primary joining technology for vehicles using aluminum. SPR are mechanical joining elements that are used to connect sheets to create a structure to build a body in white (BiW). To ensure the structural performance of a vehicle in crash load cases it is necessary to describe physical occurring failure modes under overloading conditions in simulations. One failure mode is joint separation which need to be precisely predicted by a crash simulation. Within crash simulations a detailed analysis of a SPR joint and its process history would require a very high computational effort. The conflict between a detailed SPR joint and a macroscopic vehicle model need to solved by developing an approach that can handle an accurate macroscopic prediction of SPR behavior with a defined strength level with less computational effort. One approach is using a cohesive material model for a SPR connection.
2017-03-28
Technical Paper
2017-01-1474
Raed E. El-Jawahri, Agnes Kim, Dean Jaradi, Rich Ruthinowski, Kevin Siasoco, Cortney Stancato, Para Weerappuli
Sled testing simulating a full-frontal rigid barrier impacts were conducted using the Hybrid III 5th female and the 50th male anthropomorphic test devices (ATDs). The ATDs were positioned in the outboard rear seat of a generic small car environment. Two belt configurations were used: 1) a standard belt with no load limiter or pre-tensioner and 2) a seatbelt with a 4.5 kN load-limiting retractor with a stop function and a retractor pre-tensioner (LL-PT). In the current study, the LL-PT belt system reduced the peak responses of both ATDs. Probabilities of serious-to-fatal injuries (AIS3+), based on the ATDs peak responses, were calculated using the risk curves in NHTSA’s December 2015 Request for Comments (RFC) proposing changes to the United States New Car Assessment Program (US-NCAP). Those probabilities were compared to the injury rates (IRs) observed in the field on aggregate and point estimate bases.
2017-03-28
Technical Paper
2017-01-1473
Ling zheng, Yinan Gao, Zhenfei Zhan, Yinong Li
Several surrogate models such as radial basis function and Kriging models are developed to speed the optimization design of vehicle body and improve the vehicle crashworthiness. The error analysis is used to investigate the accuracy of different surrogate models. Furthermore, the Kriging model is used to fit the model of B-pillar acceleration and foot well intrusion. The multiquadric radial basis function is used to fit the model of the entire vehicle mass. These models are further used to calculate the acceleration response in B-pillar, foot well intrusion and vehicle mass instead of the finite element model in the optimization design of vehicle crashworthiness. A multi-objective optimization problem is formulated in order to improve vehicle safety performance and keep its light weight. The particle swarm method is used to solve the proposed multi-objective optimization problem.
2017-03-28
Technical Paper
2017-01-1461
Sanketh Gowda, Anindya Deb, Goutham kurnool, Clifford Chou
Adhesively bonded steel hat section components have been experimentally studied in the past as a potential alternative to traditional hat section components with spot-welded flanges. One of the concerns with such components has been their performance under axial impact loading as adhesive is far more brittle as compared to a spot weld. However, recent drop-weight impact tests have shown that the energy absorption capabilities of adhesively bonded steel hat sections are competitive with respect to geometrically similar spot-welded specimens. Although flange separation may take place in the case of a specimen employing a rubber toughened epoxy adhesive, the failure would have taken place post progressive buckling and absorption of impact energy.
2017-03-28
Technical Paper
2017-01-1438
Felix Lee, Peter Xing, Mike Yang, Janice Lee, Craig Wilkinson, Gunter Siegmund
The accuracy and repeatability of crash data recorded by Generation 1, 2 and 3 Toyota Event Data Recorders (EDRs) in low-severity events were previously studied. The Toyota airbag control modules (ACMs) were subject to haversine acceleration pulses, and then the sensitivity of ACM response to characteristics of the crash pulse, EDR generation, and vehicle model was assessed. Linear regression models were created to accurately predict the reference speed change with a known ACM-reported speed change, pulse duration, peak acceleration, and vehicle model. The objectives of the present study are (i) to determine if accuracy trends in low-severity crashes can be applied to mid-severity collisions and (ii) to confirm our hypothesis that the ACMs function similarly on a sled as they did in a car, by comparing the response of ACMs subject to haversine, vehicle-to-vehicle, and vehicle-to-barrier collision pulses.
2017-03-28
Technical Paper
2017-01-1420
Kirsten White, Raymond Merala
Consumers and fleet managers are progressively installing or requiring the use of after-market onboard vehicle cameras, often with GPS capabilities. Some of these Video, Acceleration, and Position (VAP) devices record kinematic data including position, speed, and acceleration. Many consumers also make use of smart phone applications (apps) which provide similar features. As use of “dashcams” becomes more prevalent it follows that the accident reconstructionist may be called to analyze the video and data recorded by the devices. This study characterizes the accuracy and precision of several VAP devices, including a dashcam with GPS which is used by taxi companies nationwide, and several smart phone apps. Tests were performed in which vehicle kinematic data were recorded in a variety of real world conditions simultaneously by the VAP devices, accelerometers, and a proven GPS-based speed sensing and data acquisition system.
2017-03-28
Technical Paper
2017-01-0074
Jia Mi
Owing to the rapid development in urbanization and automotive industry, the existing fix period traffic lights has longer been an optimal solution for modern traffic flow control. Dedicated Short Range Communication (DSRC) is an advanced protocol for inter-vehicular communication, which has good stability and has been widely used in Electronic Toll Collection(ETC) . This paper proposes an intelligent traffic lights control system based on DSRC to optimal the traffic flow within acceptable computational effort and cost for the OBU has a high rate of assembly. This paper firstly provide a detailed description for the system configuration and control strategy of the whole system. The proposed system is consisted with Roadside Unit(RSU), On-board Unit(OBU) and data processor. RSU collected the traffic information by OBU through wireless information and send to data processor.
2017-03-28
Technical Paper
2017-01-1421
Brian M. Boggess, Douglas Morr, Ashley Dunn, Harold Ralston, Elaine Castro, Bryan Strawbridge
Accident reconstruction often involves the analysis of lane change dynamics that may have led to an accident, or conversely may have avoided such. These analyses can include many scenarios; one typical scenario is the merging of an articulated commercial vehicle from a roadway shoulder into a travel lane. A review of currently available analytical and computer simulation models finds that most models are based on an analysis of a single-point object. Additionally, these models consider either a constant lateral acceleration profile or a half-sine acceleration profile with specified peak lateral acceleration resulting in a constant lane change time regardless of vehicle speed. When considering the actual lane change dynamics of a tractor-trailer, the typically applied predictive models are limited to predicting the dynamics of a singular point on the tractor-trailer during the lane change as opposed to more specific dynamics of the tractor or trailer itself.
2017-03-28
Technical Paper
2017-01-1435
Yucheng Liu
A data acquisition system along with a sensor package was designed and installed on an existing mechanically-controlled cargo tractor to gather more data on their usage patterns. The data collected through the developed system include GPS route, vehicle speed and acceleration, engine state, transmission state, seat occupancy, fuel level, and video recording. The sensor package was designed and integrated in a way that does not interfere with the driver’s operation of the cargo tractor. Cellular network connectivity was employed to retrieve sensor data so as to minimize human effort and maintain typical usage patterns of the outfitted cargo tractors. Testing and validation results showed that the developed system can correctly and effectively record data necessary for further analysis and optimization. A fuel usage analysis was then completed using a chassis dynamometer based on the collected data.
2017-03-28
Technical Paper
2017-01-1410
Richard F Lambourn, James Manning
It occasionally happens, following a collision between a car and a pedestrian or in a deliberate assault with a motor vehicle, that the pedestrian comes to be caught or wedged beneath the car, and that the driver then travels on for a considerable distance, afterwards claiming to have been unaware of the presence of the person. In such incidents, investigators are often incredulous that the driver should not have been able to “feel” that there was something underneath his car, and that he did not stop at least to find out what the problem was. The only practical way of investigating the matter further is to carry out practical tests with a suitable car and dummy. This paper describes the tests performed by the authors following one such incident, and begins with accounts of two previous incidents investigated in a more subjective fashion.
2017-03-28
Technical Paper
2017-01-0379
Tau Tyan, Leonard Shaner, Matt Niesluchowski, Nand Kochhar, Dilip Bhalsod, Jason Wang PhD
Three computational fluid and gas dynamic methods, UP (Uniform Pressure), ALE (Arbitrary Lagrangian and Eulerian), and CPM (Corpuscular Particle Method), were investigated in this research in an attempt to predict the responses of side crash pressure sensors. Acceleration-based crash sensors have been used extensively in the automotive industry to determine the restraint system firing time in the event of a vehicle crash. The prediction of acceleration-based crash pulses by using computer simulations has been very challenging due to the high frequency and noisy responses obtained from the sensors, especially those installed in crush zones. As a result, the sensor algorithm developments for acceleration-based sensors are largely based on prototype testing. With the latest advancement in the crash sensor technology, side crash pressure sensors have emerged recently and are gradually replacing acceleration-based sensor for side crash applications.
2017-03-28
Technical Paper
2017-01-0268
Venkatesh Babu, Richard Gerth
Friction Stir Processing (FSP) has been used to refine grain structure in sheet metals, and is based on friction stir welding (FSW) principles developed and patented by TWI Ltd, Cambridge, UK in 1991. In Friction Stir Processing (FSP) a tool generates heat from friction and pressure causing a material to become plastic without melting. The tool then mixes the base material in a circular motion as it traverses laterally through the material . It is possible to add 2D or 3D Nano particles to locally alter the material’s stiffness (young’s modulus). For example in, friction stirred TiB2 particles in cast iron resulted in over 2x hardness and wear resistance (by ASTM G35). Since FSP is not a forming process, the pattern of the ribs can be any 2D pattern (linear, circular, spiral, etc.). The main focus of the Nano-reinforced FSP is to achieve increased localized stiffness with minimal increase in density of the local material to achieve light weighting.
2017-03-28
Technical Paper
2017-01-0377
Peter Shery, William Altenhof, Ryan Smith, Elmar Beeh, Philipp Strassburger, Thomas Gruenheid
Cylindrical extrusions of magnesium AZ31B were subjected to quasi-static axial cutting and compression modes of deformation to study this alloy’s effectiveness as an energy absorber. For comparison, the tests were repeated using extrusions of AA6061-T6 aluminum of the same geometry. Axial cutting of AA6061-T6 extrusions has been shown to be an effective, ductile mode of energy dissipation, yielding a repeatable, nearly constant load/deflection response with a crush force efficiency (CFE) up to 96%. In the present tests, the quasi-static cutting deformation of AZ31B extrusions achieved a respectable CFE of 80%, but revealed a load/deflection response with sharp, minute, rapid fluctuations, indicating an undesirable fracturing failure. Additionally, the average specific energy absorption (SEA) of AZ31B was 11 kJ/kg, which is less than half that seen for AA6061-T6 extrusions of the same geometry (24 kJ/kg).
2017-03-28
Technical Paper
2017-01-0368
Ying Zhao, Fangwu Ma, Longfan Yang, Yueqiang Wang, Hongyu Liang
The conventional hood with single material and stiffener structural form conceals some limitations on pedestrian protection and lightweight, not satisfying the requirements of structural strength, pedestrian protection and lightweight contradictory with each other at the same time. In this paper, a novel type hood is proposed to develop sandwich structure using architected cellular material with negative Poisson's ratio (NPR) configuration based on the decoupling thought of structural strength and energy absorption. Core-layer aluminum alloy material with NPR is used to meet the requirement of impact energy absorption, inner and outer skin using carbon fiber is selected to achieve high structural stiffness needed. This paper starts from the relations between geometric parameters of core-layer architected cellular material and mechanical properties, on this basis, the optimal geometric parameters can be expected using the multiobjective optimization method.
2017-03-28
Technical Paper
2017-01-1469
Tao Wang, Liangmo Wang, Jingxing Liu
To investigate the crashworthiness capacity of a M1 type commercial vehicle, the full-scale finite element (FE) model of the vehicle has been established. On basis of the FE model, the impact simulation subject to the 100% frontal impact has been carried out, and the results have been verified with the physical impact test. The analysis of the deformation path and the energy absorption indicates that the M1 vehicle lacks sufficient frontal deformation area and its peak crash acceleration (PCA) is too high, which raises a huge challenge for the sequent development of a safety restraint system. To enhance the crashworthiness of the M1 vehicle, some structural improvements have been implemented, with adding the energy absorbing box, improving the frontal frame parts and enhancing the front door. The frontal collapsing area has been investigated in order to figure out the layout position of the energy absorbing box.
2017-03-28
Technical Paper
2017-01-1440
Shixing Chen, Ming Dong, Jerry Le, Mike Rao
Vehicle safety systems may use occupant physiological information, e.g., occupant heights and weights to further enhance occupant safety. Determining occupant physiological information in a vehicle, however, is a challenging problem due to variations in pose, lighting conditions and background complexity. In this paper, we present two novel occupant height estimation approaches. In the first (2D) approach, by detecting the occupant’s eye level, the seating height of the occupant is first computed based on the distance from a conventional camera to the occupant’s head, which is then adjusted for the seat angles received from the seat angle sensors. In the second (3D) approach, we use additional depth information from a depth camera, e.g., Microsoft Kinect. In the 3D approach, we first detect human body and frontal face views (restricted by the Pitch and Roll values in the pose estimation) based on RGB and depth information.
2017-03-28
Technical Paper
2017-01-1470
Prasad S. Mehta, Prasad Tapkir
The crashworthiness of a vehicle is an important factor that needs to be considered during vehicle component design. The components sustaining the axial loads and the traverse loads are the prominent contributor as far as crashworthiness of the vehicle is concerned. The B-pillar is the crucial vehicle component responsible to absorb the side impact during the side car crash, whereas S-rail is supposed to face axial loads. This paper aims to have an optimized material density distribution (topology optimization) as well as thickness variation (Design optimization) in case of the B-pillar and S-rail that have maximum energy absorption during the side crash event of the car. Initially, B-pillar was extracted from the Toyota Camry car model, whereas standard S-rail geometry is considered for the non-linear finite element analysis. The explicit code of LS-DYNA is used to perform non-linear analysis on B-pillar and S-rail. The analysis is performed according to FMVSS regulations.
2017-03-28
Technical Paper
2017-01-1414
William Bortles, David Hessel, William Neale
When the steer axle of a vehicle with protruding wheel studs makes contact with another vehicle or object in a sideswipe configuration, the tires and wheel studs of the vehicle can deposit distinct geometrical patterns onto the surfaces it contacts. Prior research has demonstrated how relative speeds between the two vehicles and surfaces can be calculated through analysis of the distinct patterns. This paper presents a methodology for performing this analysis by visually modeling the interaction between wheel studs and various surfaces, and presents a method for automating the calculations of relative speed between vehicles. This methodology also augments prior research by demonstrating how the visual modeling and simulation of the wheel stud contact can extend to almost any surface interaction that may not have any previous prior published tests, or test methods that would be difficult to setup in real life.
2017-03-28
Technical Paper
2017-01-1433
Enrique Bonugli, Joseph Cormier, Matthew Reilly, Lars Reinhart
The purpose of this study was to determine the frictional properties between the exterior surface of a motorcycle helmet and ‘typical’ roadway surfaces. These values were compared to abrasive papers currently recommended by government helmet safety standards and widely used by researchers in the field of oblique motorcycle helmet impacts. A guided freefall test fixture was utilized to obtain nominal impact velocities of 5, 7 and 9 m/s. The impacting surfaces were mounted to an angled anvil to simulate off-centered oblique collision. Head accelerations and impact forces were measured for each test. Analysis of the normal and tangential forces imparted to the contact surface indicated that the frictional properties of abrasive papers differ from asphalt and cement in magnitude, duration and onset. Reduction in head acceleration, both linear and angular, were observed when asphalt and cement were used as the impacting surface.
2017-03-28
Technical Paper
2017-01-1423
Alan F. Asay, Christopher D. Armstrong, Bradley Higgins, John Steiner
Traditional accident reconstruction analysis methodologies include the study of the crush-energy relationship of vehicles. The process of estimating crush-energy and delta-v in real world collisions is primarily based upon a comparison of structural crush between a vehicle involved in a real world collision with that of a test vehicle. This process is well known and documented in the scientific literature. However, this process is limited to both the availability of the crash test data and the proximity of the structure engaged on the vehicle in the test. The largest source of publically available crash tests is the National Highway Traffic Safety Administration (NHTSA) crash tests database. NHTSA has conducted numerous Federal Motor Safety Vehicle Standard (FMVSS) compliance and New Car Assessment Program (NCAP) crash tests of many passenger cars and pickup trucks sold in the United States.
2017-03-28
Technical Paper
2017-01-1431
Ke Dong, Brian Putala, Kristen Ansel
Out-of-position (OOP) driver tests were designed to address concerns about airbag introduced injury in situations while the occupant is nearer to the airbag module than in a normal seated position. The 5th percentile female has instrumentation for measuring ATD sternum displacement (potentiometer) and acceleration (accelerometers) which can be used to compute compression rate. This paper documents a study investigating the capability of the chest accelerometers to accurately assess non-distributed loading of the chest during this test configuration. The study included ATD mechanical loading and instrumentation review. Finite element analysis was conducted using a Hybrid 3 - 5th percentile female ATD correlated to testing. The correlated restraint model was utilized with a Hybrid 3 – 50th percentile male ATD. A 50th percentile male Global Human Body Model was then applied for enhanced anatomical review.
2017-03-28
Technical Paper
2017-01-1437
William Bortles, Sean McDonough, Connor Smith, Michael Stogsdill
The data obtained from event data recorders found in airbag control modules, powertrain control modules and rollover sensors in passenger vehicles has been validated and used to reconstruct accidents for years. Recently, a system has been introduced that will allow crash investigators and reconstructionists to access, preserve and analyze data from infotainment and telematics systems found in passenger vehicles. The infotainment and telematics systems in select vehicles retain navigation data in the form of tracklogs that provide a time history of vehicle geolocation that may be useful in reconstructing a crash. This paper presents testing in which the GPS navigation data imaged from the vehicle is compared to independent GPS instrumentation to analyze the accuracy of the retrieved navigation data.
2017-03-28
Technical Paper
2017-01-1412
Christopher H. Goddard, David Price
Various mechanisms have been used to drive speedometers and other instrument gauges. This paper reviews the mechanisms used; in particular investigates the ability of stepper motors which have become the most common instrument motor in the last decade to freeze at the apparent reading prior to impact. Stepper motors require power to drive the needle to any indicated position, including having to return it to zero. Hence if power to the instrument is lost as a result of a collision, there is no power to move the needle and it should be left at the reading shown at the moment the power was lost. However, not all stepper motor instruments are the same and before accepting the reading, a number of criteria need to be considered to give a level of confidence in the result. As part of recent ITAI (Institute of Traffic Accident Investigators) crash test events in the UK, a number of instrument clusters were installed in vehicles to simulate both frontal and side impacts.
2017-03-28
Technical Paper
2017-01-1413
Nathan A. Rose, Neal Carter, David Pentecost, Alireza Hashemian
This paper investigates the dynamics of single-vehicle motorcycle crashes that occur on curves and identifies rider actions that contribute to causing these crashes. Physical evidence and physical principles that would enable a reconstructionist to determine when these actions are present in a particular crash are identified. The investigation is carried out by analyzing video footage of 10 motorcycle crashes that all occurred on a particular curve (Edwards Corner) on a section of the Mulholland Highway called “The Snake.” This section of highway is located in the Santa Monica Mountains of California. All of the video footage of these crashes was captured by a videographer who regularly takes video of motorcyclists traversing this curve and posts crash videos on YouTube. To aid evaluation of these crashes, the authors mapped Edwards Corner using both a Sokkia total station and a Faro laser scanner.
Viewing 1 to 30 of 3484

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