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How Crash Testing Works

An Actual Crash Test
The National Highway Traffic Safety Administration (NHTSA) conducts two types of crash tests as part of the New Car Assessment Program.

  • 35-mph frontal impact - At 35 mph (56 kph), the car runs straight into a solid concrete barrier. This is equivalent to a car moving at 35 mph hitting another car of comparable weight moving at 35 mph.

  • 35-mph side impact - A 3,015-pound (1,368-kg) sled with a deformable "bumper" runs into the side of the test vehicle. The sled's tires are angled. The test simulates a car that is crossing an intersection being sideswiped by a car running a red light. The sled actually moves at 38.5 mph, but when you do the math, it is equivalent to a 35-mph side impact because of the way the wheels on the sled are angled.

Photo courtesy NHTSA
Click on this image for a video of an actual crash test.
(Video time: 2 min, 33 sec)

Crash Test Paint
Before the crash-test dummies are placed in the vehicle, researchers apply paint to them. Different colors of paint are applied to the parts of the dummies' bodies most likely to hit during a crash. The dummy's knees, face and areas of the skull are each painted with a different color. In the following photo, you can see that the blue paint from the dummy's face is smeared on the airbag and that his left knee (painted red) hit the steering column.

Photo courtesy NHTSA
The multicolored paint on the dummy shows where the different body parts hit the car.

If researchers note a particularly large acceleration in the data from the accelerometers in the dummy driver's head, the paint marks in the car will indicate what part of the body hit what part of the vehicle inside the cabin. This information helps researchers develop improvements to prevent that type of injury in future crashes.

Photo courtesy NHTSA
The front passenger-side dummy's knees hit the dashboard during the crash. Also, note that nothing from the engine compartment penetrated the cabin. The engine on most cars is mounted so that in a crash, it is forced backwards and downward so that it won't come into the cabin.

Now, let's take a look at a 35-mph frontal-impact test.

Vehicle Setup
The photo below shows a van that is ready to crash. The dummies have been placed in the car and are in position. All of the instrumentation on the car and dummies has been hooked up and checked. Ballast is added to the car so that the crash-test vehicle's weight -- and the distribution of that weight -- is equal to that of a fully loaded vehicle. A speed sensor has been mounted to the car and positioned so that it will pass through a pickup just as the car hits the barrier.

Photo courtesy NHTSA
A minivan in front of a barrier (note the camera's speed sensor)

There are 15 high-speed cameras, including several under the car pointed upward. They shoot around 1,000 frames per second. Next, the car is backed away from the barrier and prepared to crash. A pulley, mounted in a track, pulls the car down the runway. The car hits the barrier at 35 mph. It only takes about 0.1 seconds from the time the car hits the barrier until it stops.

After the Crash
Let's take a look at some pictures. This car got four stars for both occupants in this frontal-crash test.

Photo courtesy NHTSA
The front of the same car, before and after the test

As you can see, the front of the car is completely crushed after the test. This is good, as the car has to get crushed and collapse in order to absorb the kinetic energy and stop the car.

Photo courtesy NHTSA
A better view of the front crushing

The front of the van is crushed up to the front wheels, which are pushed back. In this crash, the van actually got 23 inches (58 cm) shorter!

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