Whats the purpose of checkered marks in crash tests?
They are reference points for the film and video recordings used during the tests. Each marker is measured in relation to the others before the test starts. Then, when the films are being reviewed and studied, the markers can be use for frame by frame comparisons for speed, acceleration, movement and distortions caused by metal bending and warping, etc. For example, if two markers are measured at exactly foor feet apart at the beginning of the test, and are measured at three feet, nine inches apart at the end of the test, the scientists will know that an impact at X mph will cause the structure to compress three inches between those two points.