| Change of Velocity and Pulse Characteristics in Rear Impacts; Real World & Vehicle Test Data
Impact severity in collisions that can cause softtissue neck injuries are most commonly specified interms of change of velocity. However, it has been shown from real-world collisions that mean accel-eration influences the risk of these injuries. For a given change of velocity this means an increased risk for shorter duration of the crash pulse. Furthermore, dummy response in crash tests has shown to vary depending on the duration of the crash pulse for a given change of velocity. The range of duration for change of velocities suggested for sled tests that evaluate the pro-tection of the seat from soft tissue neck injuries are still to be established. The aim of this study was to quantify the variation of duration of the crash pulse for vehicles impacted from the rear at change of velocities suggested in test methods that evaluate the protection from soft tissue neck injuries. Crash pulses from the same vehicle models from different generations in real-world collisions producing a similar change of velocity were also analysed.
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Update on the Pedestrian Crash Data Study
In July 1994, a Pedestrian Crash Data Study (PCDS) was initiated within the United States to collect detailed crash reconstruction data on pedestrian crashes. Information on the first eighteen months of data collection was presented in a paper titled "Pedestrian Crash Data Study - An Interim Evaluation" at the ESV Conference held in June 1996. This paper will report on the continued progress and data collection efforts of the PCDS. It will report on the procedures implemented to sanitize the video recordings which are part of the data collection process for vehicle and scene documentation, and report on the continued successful implementation of the pedestrian contour gauge for the documentation of the pedestrian's contacts with the vehicle. Additional analyses of the pedestrian crash circumstances, including pre-crash, at crash, and injury consequences will also be discussed for 292 crashes.
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Train Crashworthiness Design for Occupant Survivability
Studies were conducted evaluating the effectiveness of alternative strategies for providing crashworthiness of the vehicle structures. Conventional practice results in cars of essentially uniform longitudinal strength. The crash energy management approach requires varying strength through the train, with high strength in the occupied areas and lower strength in the unoccupied areas.
For train-to-train collisions at closing speeds above 70 mph, the crash energy management approach is more effective than the conventional approach in preserving occupant volume. For closing speeds below 70 mph, both strategies are equally effective in preserving occupant volume. The crash energy management design results in gentler secondary impacts for train-to-train collisions than the conventional design, at all speeds analyzed.
A method for developing the crush zone force/displacement characteristics and occupant volume strength required to limit secondary impact velocities and preserve occupant volumes is developed. Ideal force/ displacement characteristics and occupant volume strength required to survive a 140 mph train-totrain collision are first determined; constraints on crush zone length and maximum occupant volume strength are then applied.
The two design approaches are evaluated in terms of occupant volume lost and secondary impact injury by applying a lumped-mass model, using the parameters associated with each design, for a range ofcollision scenarios.
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The year has already begun with many exciting new things happening. We just finished our 3rd CDR User's Conference in Houston, TX. This conference sold out with 270 participants, making this the largest conference we have hosted to date. We also shipped Volume 2, Issue 2 of Collision Magazine in late December. This issue turned out to be quite a bit bigger than we expected with feature articles, ARC-CSI 2007 conference DVD and many other features. We are now working on prepping for Volume 3, Issue 1 of Collision and also finalizing schedules and crashes for this year's ARC-CSI Crash Conference.
Each month the ARC Network tries to figure out what new features, new research, new promotion, basically new things you would like to see added to or improved upon in the ARC Network. We call this the "Value Add" to being a part of the ARC Network. The only problem with value add is that it is in the eye of the user. What we might think is valuable to you, may not actually be considered valuable or useful. To take the guess work out, we are creating a quick survey that will help us develop areas of the ARC Network that are valuable and useful to you. As a thank you for completing this quick survey, we will either extend your current ARC membership 2 free months or, if you are a new member, give you a 2-month free trial membership. This survey will be emailed to the Newsletter Database the week of February 25, 2008.
We are now accepting early registration for the 2008 ARC-CSI Crash Conference. This is the annual crash conference held in Las Vegas and includes fully instrumented crash testing and speaker presentations. This year the crash testing will include, pedestrian crashes, motorcycle crashes, rollover, PIT maneuver crashes, and car-to-car. We will also have industry leaders speaking on a variety of topics and 3 workshops to sharpen your skills in pedestrian accident reconstruction, rollovers and motorcycles.
>> Click here for complete information and to register
 The ARC Network has completed importing the rest of the motorcycle specs to the online motorcycle database located in the members only section of the ARC Network. This database now has data for over 3800 motorcycles covering Aprilia, Benelli, Beta, Bimoto, BMW, Buell, Cagiva, Ducati, Harley Davidson, Honda, Husaberg, Husqvarna, Hyosung, Kawasaki, KTM, Laverda, Moto Guzzi, MV Augusta, Suzuki, Triumph and Yamaha. The motorcycle specs database is free to use for all ARC Network members.
In an effort to communicate information regarding Crash Data Retrieval, I Got Hit LLC (sister company to the ARC Network) is currently developing a quarterly CDR newsletter. We are looking for volunteers to provide content such as case studies, pictures, tech tips, news, legislation, etc. If you are interested in participating, please email Scott Baker
Collision Publishing LLC is currently working on Volume 3, Issue 1 of Collision: The International Compendium for Crash Research. If you have an article you would like included in this issue or a future issue, please email it to Collision Publishing.
If you would like to subscribe to Collision or purchase any of the back issues, please visit www.collisionpublishing.com or ask your local accident reconstruction organization if the are an industry partner with Collision for a discounted subscription.
Thank you for supporting the ARC Network and subscribing to the Accident Reconstruction Newsletter.
Scott Baker
President
ARC Network LLC
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Biomechanics of side impact: Injury criteria, aging occupants, and airbag technology
This paper presents a survey of side impact trauma-related biomedical investigations with specific reference to certain aspects of epidemiology relating to the growing elderly population, improvements in technology such as side airbags geared toward occupant safety, and development of injury criteria. The first part is devoted to the involvement of the elderly by identifying variables contributing to injury including impact severity, human factors, and national and international field data. This is followed by a survey of various experimental models used in the development of injury criteria and tolerance limits. The effects of fragility of the elderly coupled with physiological changes (e.g., visual, musculoskeletal) that may lead to an abnormal seating position (termed out-of-position) especially for the driving population are discussed. Fundamental biomechanical parameters such as thoracic, abdominal and pelvic forces; upper and lower spinal and sacrum accelerations; and upper, middle and lower chest deflections under various initial impacting conditions are evaluated. Secondary variables such as the thoracic trauma index and pelvic acceleration (currently adopted in the United States Federal Motor Vehicle Safety Standards), peak chest deflection, and viscous criteria are also included in the survey. The importance of performing research studies with specific focus on out-of-position scenarios of the elderly and using the most commonly available torso side airbag as the initial contacting condition in lateral impacts for occupant injury assessment is emphasized.
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 LARGE TRUCK CRASH CAUSATION STUDY IN THE UNITED STATES
Gary R. Toth, Gregory A. Radja, Kristin K. Thiriez, Joseph S. Carra
National Highway Traffic Safety Administration
Paper Number 252
The United States Department of Transportation has been conducting a major study on the causes of large truck crashes. An unprecedented database containing highly detailed data (over 1,000 data elements) on 1,000 serious large truck crashes is being created. When completed, it will be the most comprehensive database on large truck crashes in existence. The database will be made widely available to researchers around the world.
This paper will describe the many pieces of information in the database and the countless uses of the data. Specific examples will be discussed that illustrate the richness, depth, quality, and the variety of the data.
The paper will also discuss the methods being used to capture and describe the contributing factors and the events that led up to each crash, as well as illustrate the added value of collecting data on-scene, immediately after the crash.
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TRAVELLING SPEED AND THE RISK OF CRASH INVOLVEMENT
by Kloeden CN, McLean AJ, Moore VM, Ponte G
NHMRC Road Accident Research Unit
The University of Adelaide
The main aim of this project was to quantify the relationship between free travelling speed and the risk of involvement in a casualty crash, for sober drivers of cars in 60 km/h speed limit zones in the Adelaide metropolitan area.
The secondary aims of the project were to examine the effect of hypothetical speed reductions on the crashes in this study and to explore the relationship between travelling speed and driver blood alcohol concentration.
Using a case-control study design, the speeds of cars involved in casualty crashes were compared with the speeds of cars not involved in crashes but travelling in the same direction, at the same location, time of day, day of week, and time of year. The conditions imposed on the selection of case vehicles were designed to ensure that the study would yield valid estimates of the relative risk of a car travelling at a free speed in a 60 km/h zone becoming involved in a casualty crash compared to the risk for a car travelling at 60 km/h. Data collection was concentrated during the hours of 9:30am-4:30pm, Monday to Friday as these times had the highest number of nonalcohol- related crashes in Adelaide. Some cases were also collected at nights and on weekends. The pre-crash travelling speeds of the case vehicles were determined using computer-aided accident reconstruction techniques. This was made possible by the detailed investigation of each crash at the scene which provided the physical evidence needed for input to the computer reconstruction program (M-SMAC).
Additional information about the effects of travelling speed was obtained by calculating what the results of the crash would have been if the case vehicle had been travelling at a different speed. A separate study was set up to measure the relationship between blood alcohol concentration and travelling speed. The speed of an approaching car was measured 200-300 metres before a signalised intersection using a laser speed meter. When the car stopped at this intersection for a red light, the driver was approached and asked to blow into a breath alcohol meter.
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