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You had to be there.
By Joseph E. Badger It was a gathering of the Who�s Who in accident reconstruction. More than 500 accident reconstructionists from some 40 states, the District of Columbia, and eleven other countries met in a week-long session that involved the intentional crashing of automobiles and motorcycles. Participants turned over semitrailers, changed dozens of tires on a pickup truck, examined headlights and taillights, and shot up a year�s supply of film and videotape. Individuals and members of reconstruction organizations came from around the world. Delegates represented seven provinces of Canada and four Australian states. Countries represented included Argentina, Belgium, China (Hong Kong), England, Israel, New Zealand, the Netherlands and South Africa. Hosted by the Texas Association of Accident Reconstruction Specialists (TAARS) and 21 other nonprofit accident investigation/reconstruction organizations, this exposition was the largest AI/AR conference ever. There were over 60 members of the International Network of Collision Reconstructionists (INCR) on hand.
One of the best things about a conference of this sort is that you get to rub elbows with people you have met only electronically. Comprising this eclectic collection were active and former law enforcement personnel, engineers, academics and others whose occupations or have vocations and something to do with searching for the truth concerning traffic accidents. The logistics of putting together such a symposium is mind-boggling. Imagine trying to coordinate lodging in nine hotels with activities on two campuses, plus arranging catered meals for more than 500 participants. Then there�s the transportation of these people, not only to Texas A&M University�s main campus for general sessions and to its Riverside Campus, but also to shuttle people all day on two separate occasions to various venues. Riverside Campus is home to the Texas Engineering Extension Service (TEEX). Situated among a complex configuration of concrete runways once used by U.S. military aircraft, TEEX and Texas Transportation Institute (TTI) provide excellent proving grounds for all manners of training, testing and research. One day featured 14 different sessions dealing with some diverse elements within the accident reconstruction community. There were lectures on "Vehicle Restitution," "Alcohol Involvement," "Estimating Uncertainties in Calculations," and those little "black boxes" officially known as Event Data Recorders. One of the presentations explained some of the methods used by the Dutch to gather evidence in congested areas where traffic is a major problem. The Rotterdam-Rijnmond Region, which has access to a helicopter, uses the aircraft to take aerial photos of crash sites from only 50 meters above the ground. Among their arsenal of equipment is a Mercedes Benz Sprinter that they converted into a workshop. They also have a pneumatic manipulative extension tower mounted in a Volkswagen T4. The tower consists of two 1500-watt mercury vapor lamps and a camera box built on top. They use both ocular and video cameras. The Dutch agency is establishing a Photogrammetric Department to research the possibilities in this field. They are considering applications in traffic, forensic medicine and technical investigation. A presentation by Aims Research, headquartered at the University of Nottingham in England, dealt with graphics, virtual reality and animations. Between crashes, attendees could sit in on a presentation "under the big top." Located at the test facility were two large tents. In one was a presentation on motor vehicle suspension and steering, drive train and handling characteristics. A restored 1971 Corvette "rolling chassis" was on display. This chassis was a powerful 3-D visual aid for the oral presentation. There was discussion about a vehicle�s springs, axles, torsion bars, suspensions, steering components, worm gears versus rack and pinion, rear wheel steering and shock absorbers. The "Vendors� Night" was well attended. Some 40 businesses displayed their wares and talents in an atmosphere of camaraderie. People sold accident reconstruction software, books, computers, surveying equipment, animations and other services. Prior to WREX2000 getting underway, the Dallas-Houston area suffered sweltering temperatures of 112 degrees. But Mother Nature blessed the event with practically perfect weather for the entire week. Cool morning temperatures caught many off guard and some warm-blooded attendees broke out parkas to keep off the chill. They stripped off layers of clothing as the sun crawled across the square miles of old airport runways where crash tests dominated the day. For years accident reconstructionists have battled with such questions as: What�s the drag factor of a car sliding on its top? What�s the coefficient of friction of an overturned school bus or semitrailer sliding on its side? We answered those questions. Jerr-Dan Equipment of Greencastle, PA, provided two huge wreckers (valued from $175,000 to $250,000). The 30- and 35-ton capacity behemoths made light work of overturning heavy objects such as an aluminum Fruehauf MC-306 cargo tanker, a 12,940-lb., 41-ft Trailmobile semitrailer, a 1971 Carpenter Ford Chassis School Bus and a 1986 Mercury Sable. Between the wreckers and the towed objects was a Dillon ED 2000 Plus Dynamometer, or load cell, that acted as a "spring scale" to measure the force necessary to drag these things over several feet of dry (and later wet) concrete. Wreckers pulled while scores of participants made notes as they listened to the noise of metal scraping over concrete, chewing up the vehicle surfaces like cheese being rubbed over a grater. The Dillon dynamometer has a 25-ton capacity and is accurate to within plus or minus ten pounds.
A common question asked of reconstructionists is how a heavy truck�s braking situation compares to an automobile�s. We know that big commercial vehicles can�t stop in the same distance as a car at the same speed and there is a gargantuan and almost unwieldy equation to determine weight shift of a tractor- semitrailer during a skid. Sufficient data is almost never available or obtainable to make the computation; however, it is fairly certain there are "rule-of-thumb" percentages that one might use. Our goal was to determine what those percentages might be. Another issue to consider is the probable drag factor of a semitrailer or other vehicle on its side or top. So we toppled such things and measured the force required to slide them. In an effort to learn what effect air pressure has on skidding tires, a crew spent hours mounting all kinds, makes and sizes of tires onto a pickup truck. Equipped with a Vericom accelerometer, the pickup accelerated to various speeds before the driver slammed on the brakes, bringing the truck to a stop. Prior to each run, site workers checked the tires� air pressure and, during the run, they documented the pickup�s speed. Not only did they ascertain the air pressure, workers also confirmed the hardness of each tire�s rubber compound with a durometer. Our aim was to learn what appreciable differences there were between tires with 15 psi at 20 mph and others at 30 psi at 40 mph. In another venue, participants brought their drag sleds for testing. Venue leaders carefully calculated each sled�s weight, then using the device each sled�s owner determined the drag factor of a particular section of concrete runway. Later, we compared the data with the drag factor previously established with an electronic accelerometer. Then they performed statistical analyses, the results of which were made available to attendees. One consideration studied was what effect the angle of the pull would have on the resultant drag factor. While the electronic accelerometer recorded a lower average drag factor for the concrete surface than did the drag sleds, there were several tests conducted with an ASTM Friction Trailer (in both wet and dry modes). The ASTM trailer test results came significantly closer to the results obtained with the drag sleds. The New Orleans Police Department donated 21 out-of-service Kawasaki KZ 1000 police-package motorcycles, 17 of which we dutifully bashed into fixed barriers. The remaining motorcycles were crashed into stationary vehicles. You might be surprised how a motorcycle going only 30 mph can move a car laterally. Back in 1970 at UCLA, when most motorcycles had wire-spoke wheels, Derwyn Severy purposefully crashed seven Honda CB350s and a CB750 with spoke wheels into the sides of old stationary 1964 Plymouth Belvedere taxicabs in order to determine a correlation between the motorcycles� speeds and the amount of fork deformation. Today there are relatively few wire-spoke wheels on motorcycles � they mostly consist of cast aluminum. The Kawasakis tested had cast aluminum wheels and we systematically ran them into a concrete barrier and into the side of various vehicles at different speeds. According to the test literature, "Each vehicle was equipped with multiple acceleration instrumentation in all three axes." After each test, eager bystanders converged on the damaged derelicts like flies.
A test van, pickup and car came from Harris County, TX. Some of the vehicles came from TEEX. TTI, an entity within Texas A&M University, staged the three major crashes. A combination of SAE engineers and active and retired officers administered the motorcycle crashes and other events.
Site workers used "Total Station Technology" throughout the two days of crash testing. They documented crush dimensions as well as the final rest positions of crashed vehicles. In eight particular crashes, the vehicles� headlamps and tail lamps suffered significant impacts. In another venue, personnel performed lamp examinations to determine if conclusive evidence existed for proper field evaluation. While all these activities were going on, a modern museum of sorts was close by. The Federal Highway Administration has an ongoing program known as Intelligent Transportation (ITS), Commercial Vehicle Operations (CVO). The $1.5 million ITS/CVO Technology Truck is equipped with state-of-the-art instruments and various apparatus to demonstrate the latest safety devices for commercial vehicles. The 48-ft semitrailer expandable to 920 square feet contains a multimedia classroom, interactive equipment demonstrations and an in-cab simulator. The Ford Aeromax tractor with trailer has a gross weight of 76,000 pounds. You can sit at a "simulator" and learn how truckers will soon be able to "see" in their blind spots. The unit is full of trucker toys, but none of the stuff is cheap. Displayed inside the trailer are products from 86 different manufacturers. There�s an obstacle detection system, rear vision and right side cameras and monitors. There are in-vehicle information systems and pen tablet computers. If you�re driving in Saskatchewan in January you might want to see about the Automatic Ice Chain. You could even invest in an automatic tire inflation system. There�s even a Wheel-Check Indicator/Loose Wheel Nut Indicator. Such conferences as these are what we need to educate accident investigators, reconstructionists and engineers. Hopefully more departments will realize the benefit of sending their officers to these seminars. Of the 500+ that attended WREX, nearly 40% were accredited by the Accreditation Commission for Traffic Accident Reconstruction (ACTAR). Because such accreditation is becoming more meaningful to the courts, over two-dozen people who attended WREX came in a day early to take the eight-hour ACTAR test. There will never be another training conference quite like WREX 2000. Maybe there will be a WREX 2100. Don�t miss it.
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