A dummy is built from materials that mimic the physiology of the human body. For example, it has a spine made from alternating layers of metal discs and rubber pads. This is the dummy most commonly used in crash testing. These devices measure the acceleration in a particular direction . This data can be used to determine the probability of injury.
Acceleration is the rate at which speed changes.
The crash-test dummy has accelerometers all over it. There are also accelerometers in the chest, pelvis, legs, feet and other parts of the body. Notice that it is not a steady value, but fluctuates up and down during the crash. This reflects the way the head slows down during a crash, with the highest values coming when the head strikes hard objects or the airbag. Load Sensors Inside the dummy are load sensors that measure the amount of force on different body parts during a crash.