Part of the need..... part of that discussion for something like what Informed For Life provides is covered here.
Old - but still very relevant.
Quote :
NHTSA and IIHS Fail to Identify the Most Safe Vehicles
Vehicle crash tests measure
crashworthiness—the ability of a vehicle to protect the occupants during impact with a stationary barrier, such as a bridge abutment. A vehicle's weight is not indicative of its
crashworthiness—some small, light-weight vehicles have excellent
crashworthiness, while many large SUVs and pick-up trucks do not. However, when two vehicles collide head-on the relative weight of your vehicle compared with your opponent's vehicle determines the severity of forces you experience. Since 60% of traffic accidents involve multiple vehicles you must consider both
crashworthiness and size/weight to identify a safe vehicle.
There are two agencies that perform crash testing for rating the
crashworthiness of vehicles sold in the United States: The National Highway Traffic Safety Administration (NHTSA)—an agency within the U.S. Department of Transportation, and the Insurance Institute for Highway Safety (IIHS)—an organization created and funded by approximately one hundred automobile insurance companies. Crash tests performed by each agency use different protocols and their results complement each other, which is why the agencies
only agree about half the time as to which vehicles have the best
crashworthiness. You must review ratings posted by both agencies to evaluate the
crashworthiness of any vehicle.
Next, you need to interpret the ratings. This is not as easy as it may first appear considering that the majority of vehicles (60% of all 2011-2016 vehicles) are rated “Top Pick” by IIHS; 45% are rated “5-Stars Overall” by NHTSA. However, of approximately 1800 vehicles with sufficient data for evaluation, only 14% are both “Top Pick” and “5-Stars Overall”. You may be surprised to learn that many of these "Safe" vehicles
do not rate in the top
quartile in some individual crash modes. Specifically, NHTSA designates some vehicles as "5-Stars Overall" despite receiving only "4-Stars" in side impact and/or in frontal impact. Also, IIHS designates some pre-2014 vehicles as “Top Pick”, despite receiving “Poor” or “Marginal” ratings in the small-overlap frontal test. As a general rule-of-thumb your risk of serious injury/death increases 30%-50% when going from either agency's best rating category to their 2nd best, i.e., 5-stars-to-4-stars, or Good-to-Acceptable.
After you cull from the safest 14% list those vehicles with ratings below the top quartile in one or more individual crash mode, the resulting short list consists of approximately 5% of vehicles, all with top-quartile
crashworthiness ratings in every crash mode. Included within this 5% list however are light-weight vehicles that need to be removed from consideration. Although both agencies warn the consumer to avoid light-weight vehicles
their ratings data are presented without factoring in this important consideration. Separately, IIHS publishes data showing the dramatic correlation between vehicle weight and fatalities in multi-vehicle accidents. For example, these data show that drivers were twice as likely to die in a 2,500 lb. car as in a 4,000 lb. car; 4x as likely as in a 4,500 lb. SUV. These data enable you to compare fatality rates of vehicles based solely on class/weight, and as a practical matter you can avoid vehicles that have an inherent disadvantage compared with the average vehicle you are likely to collide with, such as an average weight (3,200 lb.) passenger car.
Once you remove vehicles whose class/weight have a higher driver fatality rate than the average weight passenger car, the 4% list is reduced to only 2% of vehicles. These 2% are the only vehicles judged to be “safest”.
I created this website to enable consumers to easily identify the safest vehicles.
by Mike Dulberger, Founder, Informed For Life
***
End Quote.
http://informedforlife.org/viewartcl.php?index=131
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There is a lot more to it and IFL also covers some of that elsewhere on the site.
Part of that would include that IFL closes the gap as best possible and in decent usable fashion, given the data limitations between real world result and the ratings where both IIHS and NHTSA both far more than struggle.
Another fail with NHTSA and IIHS - touched on above but well worth a more detailed look is that the rating systems ( as opposed to the physical testing which is a seperate consideration and topic ) - how scores and Stars and groupings are assigned have at least several shortcomings.
1. ) Too easy to get a 'good' net score of some kind because windows for each star rating as an example, are far too broad.
2. ) This leads to the next rating informational fail both provide ie lack of relative discernment.
So in sum, much harder and ultimately less complete in terms of allowing those interested in discerning more finely between the the so so s and the top.
One thing for certain.
Nobody would accept all these shorts including the ones not mentioned here....... which is often the bulk of it - with regard to road performance ratings and MPGs etc and soon..... with regard to EM.
IFL does a real service including by the already mentioned relating of scores to real world result. But even there and because of the inherent shorts @ NHTSA and IIHS - that could be improved as well and would be if the other two got up and really did something more useful. They also deserve a big shout out for bringing the two Testing Regimes and resulting Data sets together into something very usable which is something both IIHS and NHTSA have been steadfast in ignoring / preventing over the course of their often frosty, and sometimes outright antagonistic relationship.
