Car Crash Tests Are More Complicated Than You Think

On the surface, car crashes may seem pretty simple. You put a crash dummy in the seats and head toward a wall. We wish things were that simple, but in reality, car crash tests are much more complicated with the use of physics and biology to determine impacts and injuries

How Car Crash Tests Work 

By using injury biomechanics and crash testing, automakers have been able to gain an understanding of the amount of force that injures the human body during impacts. With this information, doctors and engineers have been able to determine how to make vehicles safer. 

2014 Ford Explorer XLT crash test
DEARBORN, MI – MARCH 10: The damaged front of a 2014 Ford Explorer XLT sits after a full-frontal crash impact test into a wall at 30mph at the Crash Barrier Dearborn Development Center March 10, 2014 in Dearborn, Michigan. (Photo by Bill Pugliano/Getty Images)

This information is vital to understanding what helps keep passengers safe in real traffic accidents and what doesn’t work to reduce the number of injuries and deaths that occur. Of course, crash tests involve basic inertia, but crash tests go beyond objects in motion to see how impacts affect organs and tissues in our bodies. 

Insurance Institute For Highway Safety Research 

The Insurance Institute for Highway Safety (IIHS) has a building with three runways set up where vehicles are tested at precise speeds using nitrogen and cables to achieve crashes with the use of realistic dummies instead of real people. 

Anti Glare lights illuminate the room, so the powerful 500 frame per second cameras can clearly catch every detail. The crashes represent real-life situations, like hitting a tree, for example, to discover injury patterns. 

Because the crash test dummies are equipped with tools to determine the force of chest or head acceleration, researchers can determine the amount of impact that would kill a passenger or not. 

Sophisticated Crash Dummies 

Also, not everyone is the same, which is why a variety of crash test dummies are used. Infant dummies to those that represent larger males are included. The baby dummies are called CRABIs for Child Restraint AirBag Interaction. 

An NHTSA employee poses with crash test dummies
An NHTSA employee poses with crash test dummies | Bill O’Leary/The Washington Post via Getty Images

Crash dummies used in side-impact crash tests have the most tools equipped with sensors from their heads to their toes. Accelerometers measure the acceleration of the force, like in the head, and load cells measure force. The ribs can even move to measure displacement. 

This information relates to people as force is applied to animal or cadaver tissue to determine how much force an area of the body can take. This allows researchers to gather how much force breaks bones or causes injuries. 

Crash Test Dummy
Crash Test Dummy | SeongJoon Cho/Bloomberg via Getty Images

The Three Crashes In Wrecks 

When a vehicle crashes, the car hits something to create an impact and comes to a stop. The bodies also move forward as they come to a halt. The organs inside of people also experience an impact as they come to a halt. For example, the lungs can hit the rib cage. 

2019 Ram 1500 IIHS crash test
2019 Ram 1500 IIHS crash test | IIHS

Stress occurs internally when one organ is firmly kept in place, but others are free to move. For example, in the heart, the ascending aorta is free to move while the descending aorta is fixed. The fixed aorta comes to a stop with the body while the ascending aorta continues forward and can tear away from the heart. 

Therefore force and acceleration can determine the stress, strain, and displacement in the body. This helps to determine if vehicles are built safely enough to protect people in traffic accidents or not.