That is a very misleading video, IMHO.
First off, those belts do not seem to have been snugged down sufficiently. It looked like there was way too much body movement. The belts have to be very, very snug in order for the HANS to work properly. When I first used my Hans, I felt 'loose' in the seat. Once we determined that you had to really snug down on the belts, I felt very secure. Prior to that we were tightening the belts 'the way we always did'.
Second, most of us do not race on a flat metal plate for a seat lacking any lateral support, such as what was tested. We racing on racing seats which do provide some lateral support. Some better than others.
Third, even though the belts slipped on the Hans, look very closely at the video and compare the total amount of head movement and neck travel of the Hans user to the non-Hans user. The Hans user still had less head and neck travel, inspite of not being used correctly i.e. the belts too loose and slipping out.
Lastly - In actual real world crashes, how often do the belts come loose in the manner shown in the video? Anybody see Brakke's crash (A Hans user) in this years E-Prod race on Speed? (If not, there is a nice photo sequence on the Prod website taken from the pit wall) Did his belts come loose? How about that IRL fire-ball crash this year by the Target driver? Did his belts come loose? How about the dozens of Nascar drivers that crash every week (probably the highest number of events to evaluate)?
To me, all that video shows is that if you don't use the safety equipment properly i.e. snug your belts down properly, proper mounting angle (which BTW is what contributed to Earnharts death), decent racing seat with some lateral support, then the Hans
might not be as effective as another device.
Edit - added link to Brakke's crash. It's on the 6th page of the thread, about halfway down:
http://www.coloradoscca.org/prodcar/viewto...r=asc&start=100