The History of Crash Test Dummies

Sierra Sam and the family of crash test dummies

Crash Test Dummies - Family
Crash Test Dummies - Family. United States Department of Transportation

The first crash test dummy was the Sierra Sam created in 1949. This 95th percentile adult male crash test dummy was developed by Sierra Engineering Co. under a contract with the United States Air Force, to be used for evaluation of aircraft ejection seats on rocket sled tests." - Source FTSS

In 1997, GM's Hybrid III crash test dummies officially became the industry standard for testing to comply with government frontal impact regulations and air bag safety.

GM developed this test device nearly 20 years ago, in 1977, to provide a biofidelic measurement tool -- crash test dummies that behave very similarly to human beings. As it did with its earlier design, Hybrid II, GM shared this cutting-edge technology with government regulators and the auto industry. The sharing of this tool was made in the name of improved safety testing and reduced highway injuries and fatalities, worldwide. The 1997 version of Hybrid III is the GM invention with some modifications. It marks another milestone in the automaker’s trailblazing journey for safety. Hybrid III is the state-of-the-art for testing advanced restraint systems; GM has been using it for years in the development of front-impact air bags. It provides a broad spectrum of reliable data that can be related to the effects of crashes on human injury.

Hybrid III features a posture representative of the way drivers and passengers sit in vehicles.

All crash test dummies are faithful to the human form they simulate -- in overall weight, size and proportion. Their heads are designed to respond like the human head in a crash situation. It is symmetrical and the forehead deflects much the way a person's would if struck in a collision. The chest cavity has a steel rib cage that simulates the mechanical behavior of a human chest in a crash.

The rubber neck bends and stretches biofidelically, and the knees also are designed to respond to impact, similar to human knees. Hybrid III crash test dummy has a vinyl skin and is equipped with sophisticated electronic tools including accelerometers, potentiometers and load cells. These measure the acceleration, deflection and forces that various body parts experience during crash deceleration.

This advanced device is being improved continuously and was built on a scientific foundation of biomechanics, medical data and input, and testing that involved human cadavers and animals. Biomechanics is the study of the human body and how it behaves mechanically. Universities conducted early biomechanical research using live human volunteers in some very controlled crash tests. Historically, the auto industry had evaluated restraint systems using volunteer testing with humans.

Twenty years ago, the development of Hybrid III served as a launching pad to advance the study of crash forces and their effects on human injury. All earlier crash test dummies, even GM's Hybrid I and II, could not provide adequate insight to translate test data into injury-reducing designs for cars and trucks. Early crash test dummies were very crude and had a simple purpose -- to help engineers and researchers verify the effectiveness of restraints or safety belts.

Before GM developed Hybrid I in 1968, dummy manufacturers had no consistent methods to produce the devices. The basic weight and size of the body parts were based on anthropological studies, but the dummies were inconsistent from unit to unit. The science of anthropomorphic dummies was in its infancy, and their production quality varied.

Some 30 years ago, GM researchers created Hybrid I by merging the best parts of two primitive dummies. In 1966, Alderson Research Laboratories produced the VIP-50 series for GM and Ford. It was also used by the National Bureau of Standards. This was the first dummy manufactured specifically for the auto industry. Then, in 1967, Sierra Engineering introduced Sierra Stan, a competitive model. Neither satisfied GM engineers, who made their own dummy by combining the best features of both -- hence the name Hybrid I.

GM used this model internally but shared its design with competitors through special committee meetings at the Society of Automotive Engineers (SAE). Hybrid I was more durable and produced more repeatable results than its predecessors.

The use of these early dummies was sparked by U.S. Air Force testing that had been conducted to develop and improve pilot restraint and ejection systems. From the late forties through the early fifties, the military used crash test dummies and crash sleds to test a variety of applications and human tolerance to injury. Previously they had used human volunteers, but rising safety standards required higher speed tests, and the higher speeds were no longer safe for human subjects. To test pilot-restraint harnesses, one high-speed sled was propelled by rocket engines and accelerated up to 600 m.p.h. Colonel John Paul Stapp shared the results of Air Force crash-dummy research in 1956 at the first annual conference involving auto manufacturers.

Later, in 1962, the GM Proving Ground introduced the first, automotive, impact sled (HY-GE sled). It was capable of simulating actual collision acceleration waveforms produced by full-scale cars. Four years after that, in 1966, GM Research originated a versatile method for determining the extent of injury hazard produced when measuring impact forces on anthropomorphic dummies during laboratory tests.

Ironically, in the past forty years, the auto industry has dramatically out-paced aircraft manufacturers in this technical expertise. As recently as the mid-1990s, automakers worked with the aircraft industry to bring them up to speed with the advances in crash testing as related to human tolerance and injuries. NATO countries were particularly interested in automotive crash research because there were problems in helicopter crashes and with high-speed ejections of pilots. It was thought that the auto data might help make aircraft safer.

When Congress passed the National Traffic and Motor Vehicle Safety Act of 1966, the design and manufacture of automobiles became a regulated industry. Shortly thereafter, debate began between the government and some manufacturers about the credibility of the test devices like the crash dummies.

The National Highway Safety Bureau insisted that Alderson's VIP-50 dummy be used to validate restraint systems.

They required 30 mile-per-hour head-on, barrier tests into a rigid wall. Opponents claimed the research results obtained from testing with this crash test dummy were not repeatable from a manufacturing standpoint and were not defined in engineering terms. Researchers could not rely on the consistent performance of the test units. Federal courts agreed with these critics. GM did not take part in the legal protest. Instead, GM improved upon the Hybrid I crash test dummy, responding to issues that arose in SAE committee meetings. GM developed drawings that defined the crash test dummy and created calibration tests that would standardize its performance in a controlled laboratory setting. In 1972, GM handed the drawings and calibrations to the dummy manufacturers and the government. The new GM Hybrid II crash test dummy satisfied the court, the government, the manufacturers, and became the standard for frontal crash testing to comply with U.S. automotive regulations for restraint systems.

GM's philosophy has always been to share crash test dummy innovation with competitors and earn no profit in the process.

In 1972, while GM was sharing Hybrid II with the industry, experts at GM Research began a ground-breaking effort. Their mission was to develop a crash test dummy that more accurately reflected the biomechanics of the human body while in a vehicle crash.

This would be called Hybrid III. Why was this necessary? GM was already conducting tests that far-exceeded government requirements and the standards of other domestic manufacturers. Right from the start, GM developed every one of its crash dummies to respond to a particular need for a test measurement and enhanced safety design. Engineers required a test device that would allow them to take measurements in unique experiments they had developed to improve the safety of GM vehicles. The goal of the Hybrid III research group was to develop a third-generation, human-like crash test dummy whose responses were closer to biomechanical data than the Hybrid II crash test dummy. Cost was not an issue.

Researchers studied the way people sat in vehicles and the relationship of their posture to their eye position. They experimented with and changed the materials to make the dummy, and considered adding internal elements such as a rib cage. The stiffness of materials reflected biomechanical data. Accurate, numerical control machinery was used to manufacture the improved dummy consistently.

In 1973, GM held the first international seminar with the world's leading experts to discuss human-impact response characteristics.

Every previous gathering of this kind had focused on injury. But now, GM wanted to investigate the way people responded during crashes. With this insight, GM developed a crash dummy that behaved much more closely to humans. This tool provided more meaningful lab data, enabling design changes that could actually help prevent injury. GM has been a leader in developing testing technologies to help manufacturers make safer cars and trucks. GM also communicated with the SAE committee throughout this development process to compile input from dummy and auto manufacturers alike. Only a year after the Hybrid III research began, GM responded to a government contract with a more refined dummy. In 1973, GM created the GM 502, which borrowed early information the research group had learned. It included some postural improvements, a new head, and better joint characteristics.

In 1977, GM made Hybrid III commercially available, including all the new design features GM had researched and developed.

In 1983, GM petitioned the National Highway Traffic Safety Administration (NHTSA) for permission to use Hybrid III as an alternative test device for government compliance. GM also provided the industry with its targets for acceptable dummy performance during safety testing. These targets (Injury Assessment Reference Values) were critical in translating Hybrid III data into safety improvements. Then in 1990, GM asked that the Hybrid III dummy be the only acceptable test device to meet government requirements. A year later, the International Standards Organization (ISO) passed a unanimous resolution acknowledging the superiority of Hybrid III. The Hybrid III is now the standard for international frontal impact testing. In fact, on September 1, 1997, it becomes the only official frontal impact test device for occupant restraint compliance testing to FMVSS208. And Hybrid III has been designated as the official test device for the new European frontal impact regulation schedules to take effect in October 1998.

Over the years, Hybrid III and other dummies have undergone a number of improvements and changes. For example, GM developed a deformable insert that is used routinely in GM development tests to indicate any movement of the lap belt from the pelvis and into the abdomen. Also, the SAE brings together the talents of the car companies, parts suppliers, dummy manufacturers and U.S. government agencies in cooperative efforts to enhance test dummy capability. A recent 1966 SAE project, in conjunction with NHTSA, enhanced the ankle and hip joint. However, dummy manufacturers are very conservative about changing or enhancing standard devices. Generally, an auto manufacturer must first show the need for a specific design evaluation to improve safety. Then, with industry agreement, the new measuring capability can be added. SAE acts as a technical clearinghouse to manage and minimize these alterations.

Just how accurate are these anthropomorphic test devices? At best, they are predictors of what may happen generally in the field because no two real people are the same in size, weight or proportions. However, tests require a standard, and the modern dummies have proven to be effective prognosticators. Crash-test dummies consistently prove that standard, three-point safety belt systems are very effective restraints -- and the data holds up well when compared to real-world crashes. Safety belts cut driver crash deaths by 42 percent. Adding air bags coupled with proper belt use raises the protection to approximately 47 percent.

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