the maximum deceleration does not exceed 60g for more than a cumulative 3ms, this being
measured only in the direction of impact
FIa tech regs on rear and front impact.
the front impact is at 14 m/s (50,4 km/h)
the rear impact is at 12 m/s (43,2 km/h)
It can reach a maximum of these values at these low speed...imagine at high speed....Schummy's impact was at 185 km/h if I'm not mistaken (at Silverstone 1999).....(there was an article in the Autosport mag the week after the accident about it)
About the NASA tests those tests when the mention a brief time they mean one or 2 tenths of a second what we're talking about here is 100 times smaller then that (ms)....
Princess Diana's accident reached between 70 and 100 G's....but it was a road car and they don't have very good seat belts, (they make the torso rotate on impact) and Diana was concious on impact.