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Originally Posted by ashishk29 The previous assertions on the thread were that a 5 star rating is meaningless/useless/pointless at anything above 64kmph. |
But you claimed a lot more than that. Not paraphrasing:
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A 5 star rated car will definitely be safe even at 100kmph
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Originally Posted by ashishk29 It will still reduce the the force of the impact that gets transferred onto the occupants. That's how physics works. |
But is it? If the crumple zone is equally engaged in both crashes, then whatever energy had to be spent in plastic deformation of load paths in the crumple zone, was spent in equal amounts in both cases. Ideally, the remaining kinetic energy should travel rearward as elastic potential energy as load paths in the crumple zone exert forces on "higher tensile" load paths in the passenger compartment.
Unfortunately, steels do not behave as kindly, linearly or even smoothly as you seem to think they do. Even higher tensile steels have a well-defined "elastic" limit where they will start to undergo sudden plastic deformation without warning. It is signs of reaching this limit that make NCAPs classify a passenger-cell load path as having failed or not, and specifically in Global NCAP and Latin NCAP the passenger compartment is rated stable only if at least two load paths have not failed (this is a heuristic you will not find in black-and-white in the protocols). Plastic deformation in the passenger compartment is undesirable because a small increase in force could cause great further deformation of the passenger cell, making the deformation measurements unreliable. That is the idea behind the -1 modifier for an unstable passenger compartment.
The point is: you have not accounted for the possibility that that very increase in force transferred to the passenger cell load paths could cause them to breach their elastic limit, beyond which they behave very differently. Yet you confidently use simple linear equations in the name of 'science' to determine force transferred to the passenger cell in an above-64km/h crash (and remember, we're being very kind to the car in assuming it's offset deformable barrier in the first place)?
Forget the IIHS, take it from ADAC, the very lab where your XUV300 was tested. Mind the German subtitles.
I reiterate, if small changes in the lab cause such high deviation in outcomes, don't expect me to infer from the bizarre crashes you've shown that stars can predict the outcomes of crashes with high confidence. You have most likely obtained a spurious correlation because your sample is not representative. I could very easily pick examples from the many gory pictures of five star cars with serious or fatal injury and zero-star cars people have walked away from, and show you a strong negative correlation between stars and protection against serious or fatal injury but there would be nothing 'scientific' or ethical about that either.
Correct me if I'm wrong, but I think the point you are trying to get across and frustrated at being unable to, is that even with all reasonable driver training, crashes will happen, so the argument of five stars being useless if the driver is bad, is futile, because five stars is for when drivers
are bad. If that is the case, I get your point. Changing the human is not a very practical solution, which is exactly why other parties involved need to take responsibility for what is in their control. That is the underlying principle of the Safe Systems approach (someone had made a thread here recently as well, I believe) which is what NCAPs, iRAPs etc. are fulfilling. But I argue that there's too little in carmakers' control for us to be telling idiots that their car is idiot-proof (excuse my language).
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I honestly don't know MotorInc or Schumi well enough to comment on your claims about his background. I am not into bikes, so I did not know him before, and I have seen only a handful of videos from them. I stand by what I've said regardless of what the video might say.