Air bag testing in the late seventies generated another need. Based on tests with crude dummies, GM engineers knew children and smaller occupants could be vulnerable to the aggressiveness of air bags. Air bags must inflate at very high speeds to protect occupants in a crash -- literally in less than the blink of an eye. In 1977, GM developed the child air bag dummy. Researchers calibrated the dummy using data gathered from a study involving small animals. The Southwest Research Institute conducted this testing to determine what impacts the subjects could safely sustain. Later GM shared the data and the design through the SAE.
GM also needed a test device to simulate a small female for testing of driver air bags. In 1987, GM transferred the Hybrid III technology to a dummy representing a 5th percentile female. Also in the late 1980s, the Center for Disease Control issued a contract for a family of Hybrid III dummies to help test passive restraints. Ohio State University won the contract and sought GM's help. In cooperation with an SAE committee, GM contributed to the development of the Hybrid III Dummy Family, which included a 95th percentile male, a small female, a six-year-old, child dummy, and a new three-year-old. Each has Hybrid III technology.
In 1996, GM along with Chrysler and Ford became concerned about air bag inflation induced injuries and petitioned the government through the American Automobile Manufacturers Association (AAMA) to address out-of-position occupants during air bag deployments. The goal is to implement test procedures endorsed by the ISO -- which use the small female dummy for driver-side testing and the six- and three-year-old dummies, as well as an infant dummy for the passenger side. An SAE committee completed work recently to develop a series of infant dummies with one of the leading test device manufacturers, First Technology Safety Systems. Newly developed six-month old, 12-month-old, and 18-month-old dummies are now available to test the interaction of air bags with child restraints. Known as CRABI or Child Restraint Air Bag Interaction dummies, they enable testing of rearward-facing infant restraints when placed in the front, passenger seat equipped with an air bag. The various dummy sizes and types, ranging from small -- to average -- to very large, allow GM to implement an extensive matrix of tests and crash-types. Most of these tests and evaluations are not mandated, but GM routinely conducts tests not required by law. In the 1970s, side-impact studies required another version of the test devices. NHTSA, in conjunction with the University of Michigan's Research and Development Center, developed a special side-impact dummy or SID. Europeans then created the more sophisticated EuroSID. Subsequently, GM researchers made significant contributions through the SAE to the development of a more biofidelic device called BioSID, which is used now in development testing.
In the 1990s, the U.S. auto industry worked to create a special, small occupant dummy to test side-impact air bags. Through USCAR, a consortium formed to share technologies among various industries and government departments, GM, Chrysler and Ford jointly developed SID-2s. The dummy mimics small females or adolescents and helps measure their tolerance of side-impact air bag inflation. U.S. manufacturers are working with the international community to establish this smaller, side-impact device as the starting basis for an adult dummy to be used in the international standard for side impact performance measurement. They are encouraging the acceptance of international safety standards, and building consensus to harmonize methods and tests. The automotive industry is highly committed to harmonized standards, tests and methods as more and more vehicles are sold to a global market.
What is the future? GM's mathematical models are providing valuable data. Mathematical testing also permits more iteration in a shorter time. GM's transition from mechanical to electronic air bag sensors created an exciting opportunity. Present and future air bag systems have electronic "flight recorders" as part of their crash sensors. Computer memory will capture field data from the collision event and store crash information never before available. With this real-world data, researchers will be able to validate lab results and modify dummies, computer-simulations and other tests. "The highway becomes the test lab, and every crash becomes a way to learn more about how to protect people," said Harold 'Bud' Mertz, a GM safety and biomechanical expert. "Eventually, it might be possible to include crash recorders for collisions all around the car," he added.
GM researchers constantly refine all aspects of the crash tests to improve safety results. For example, as restraint systems help to eliminate more and more catastrophic upper-body injuries, safety engineers are noticing disabling lower-leg trauma. GM researchers are beginning to design better lower leg responses for dummies. They have also added “skin” to the necks to keep air bags from interfering with the neck vertebrae during tests.
Someday, on-screen computer "dummies" may be replaced by virtual humans, with hearts, lungs and all the other vital organs. But it's not likely that those electronic scenarios will replace the real thing in the near future. Crash dummies will continue to provide GM researchers and others with remarkable insight and intelligence about occupant crash protection for many years to come.
A special thanks goes to Claudio Paolini