Great video, but these are not "GM" crash tests.
All of this video looks to be shot at the UCLA Institute for Transportation and Traffic Engineering, which conducted many such tests back in the 50s and 60s: http://www.engineer.ucla.edu/history/transportation.html
. The testing was not in any way funded by GM (although I think they may have provided some cars), but rather by the State of California.
Many safety features we take for granted on vehicles today resulted directly from some of this research.