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Well into the 1950s, car manufacturers tended to claim that accidents could never be made survivable – the violence was simply too much for the body to bear. But they were wrong. Thanks to a gruesome catalogue of experiments, we now know how much it takes to injure every major bone and organ in the body. The results show that if humans are packaged carefully they can withstand even severe smashes.

Dummy Basics

Crash test dummies are full-scale anthropomorphic test devices (ATD) that simulate the dimensions, weight proportions and articulation of the human body, and are usually instrumented to record data about the dynamic behavior of the ATD in simulated vehicle impacts. This data can include variables such as velocity of impact, crushing force, bending, folding, or torque of the body, and deceleration rates during a collision for use in crash tests.

Testing

Detroit’s Wayne State University was the first to begin serious work on collecting data on the effects of high-speed collisions on the human body. In the late 1930s there was no reliable data on how the human body responds to the sudden, violent forces acting on it in an automobile accident. Furthermore, no effective tools existed to measure such responses. Biomechanics was a field barely in its infancy. It was therefore necessary to employ new types of test subjects in order to develop initial data sets.

Cadaver Testing

The first test subjects were human cadavers. They were used to obtain fundamental information about the human body’s ability to withstand the crushing and tearing forces typically experienced in a high-speed accident. To such an end, steel ball bearings were dropped on skulls, and bodies were dumped down unused elevator shafts onto steel plates. Cadavers fitted with crude accelerometers were strapped into automobiles and subjected to head-on collisions and vehicle rollovers.

However, work with cadavers presented almost as many problems as it resolved. Not only were there the moral and ethical issues related to working with the dead, but there were also research concerns. The majority of cadavers available did not represent a demographic cross-section of accident victims. Since no two cadavers are the same, and since any specific part of a cadaver could only be used once, it was extremely difficult to achieve reliable comparison data. Moreover, as crash testing became more routine, suitable cadavers became increasingly scarce. As a result, biometric data were limited in extent and skewed toward the older males.

A 1995 Journal of Trauma article noted that as a result of design changes implemented up to 1987, cadaver research has since saved 8500 lives annually. For every cadaver used, each year 61 people survive due to wearing seat belts, 147 live due to air bags, and 68 survive windshield impact.

Volunteer testing

Some researchers took it upon themselves to serve as crash test dummies. Colonel John Paul Stapp USAF propelled himself over 1000 km/h on a rocket sled and stopped in 1.4 seconds. Lawrence Patrick, then a professor at Wayne State University, endured some 400 rides on a rocket sled in order to test the effects of rapid deceleration on the human body. He and his students allowed themselves to be smashed in the chest with heavy metal pendulums, impacted in the face by pneumatically-driven rotary hammers, and sprayed with shattered glass to simulate window implosion.

But while data from live testing was valuable, human subjects could not withstand tests which went past a certain degree of physical injury. To gather information about the causes and prevention of injuries and fatalities would require a different kind of subject.

Animal testing

By the mid-1950s, the bulk of the information cadaver testing could provide had been harvested. It was also necessary to collect data on accident survivability, research for which cadavers were woefully inadequate. In concert with the shortage of cadavers, this need forced researchers to seek other models. One observer noted of the Eighth Stapp Car Crash and Field Demonstration Conference;

“We saw chimpanzees riding rocket sleds, a bear on an impact swing…We observed a pig, anesthetized and placed in a sitting position on the swing in the harness, crashed into a deep-dish steering wheel at about 10 mph.”

One important research objective which could not be achieved with either cadavers or live humans was a means of reducing the injuries caused by impalement on the steering column. By 1964, over a million fatalities resulting from steering wheel impact had been recorded, a significant percentage of all fatalities. The most commonly used animal subjects in cabin-collision studies were pigs, primarily because their internal structure is similar to a human’s. Pigs can also be placed in a vehicle in a good approximation of a seated human. The ability to sit upright was an important requirement for test animals in order that another common fatal injury among human victims, decapitation, could be studied.

Although animal test data were still more easily obtained than cadaver data, the fact that animals were not people and the difficulty of employing adequate internal instrumentation limited their usefulness. Animal testing is no longer practiced by any of the major automobile makers; General Motors discontinued live testing in 1993 and other manufacturers followed suit shortly thereafter.

Recent Developments

SID (Side Impact Dummy) specially designed to measure rib, spine and internal organ shocks and compression of the chest cavity in side collisions.

BioRID is a development of the crash test dummy which helps to more accurately assess whiplash trauma from a rear impact. This proved very helpful in designing efficient head and neck restraints. The BioRID test dummy’s ability to assume a more natural seating position comes from its 24 vertebra simulators.

CRABI represents a child test dummy used to better measure the effectiveness of child restraint systems. It comes in three age versions: one 18-month year old, a 12-month and a 6-month dummy.

THOR is an advanced 50th percentile male dummy and official successor of the Hybrid III model. It features an improved spine and pelvis structure in order to better resemble a human and comes with an innovative array of face sensors meant to determine how objects impact a human face during a car crash.

i-Dummies feature a new head, upper and lower neck, chest and pelvis. The name “i” refers to integrated electronics, because this dummy model a data recorder the size of a cell phone removing 50 pounds of wires and allowing the dummy to move around more freely.

THUMS (Total HUman Model for Safety) is an advanced crash test dummy from Toyota Motor Corporation (TMC). This average male dummy builds on the previous generation (which added a bone-like structure and brain) by adding detailed models of internal organs. The THUMS 4 allows researchers and engineers to determine how and to what extent areas of the torso and internal organs are damaged during a collision.

Car safety has come a long way since the first man died in a car crash 100 years ago. But behind every sleek safety device, gruesome experiments have been conducted using human cadavers, animals and even living people.

It’s not a pleasant thing to contemplate while driving, but the design of almost every aspect of a modern car interior is based on the tolerance of different parts of the human body to violent impacts.