Vehicle manufacturers provide data / specs...
They have an approved test rig, which is then calibrated to the vehicle they are testing for...
They then crash the 'test rig'...
Have seen the testing chamber.
Printable View
A video here showing some of the testing, and the crush cans :angel:
[ame="http://www.youtube.com/watch?v=stJL4_gP5LU"]YouTube- ARB Bull Bars[/ame]
[ame="http://www.youtube.com/watch?v=Y-N1-qn5_9Q&feature=related"]YouTube- ARB Bull Bars & Airbags[/ame]