IIHS is the acronym for the Insurance Institute for Highway Safety.
This is an American organization focused on highway safety founded in 1959 by a group of insurance companies.
One of the most publicly visible areas of IIHS work is their crash safety rating system, which is developed based on crash tests in their own testing facility. This rating has real world implications, with a 5 Star IIHS rating used by manufacturers as a selling feature and by insurers as a guide to setting insurance rates.
You will be safer in a 2020 vehicle than you would be in a 2010 or 2005 vehicle in the same type of hit. You will probably be safer still in the 2021 because none of the manufacturers move backwards on safety.
The car may be more expensive to repair, but you will not care much about that if you walk away from the accident with no injury. Your insurance company should be ready to pay an extra $2,000 or $3,000 or even $10,000 to repair your car if tens or even hundreds of thousands in injury costs are saved.
5 Stars to 3
The insurance company should be ready to pay; but then we run into measurement and reward in a compartmentalized business. The insurance adjuster, and the entire claims department, is judged by the amount of money paid out; lower claim costs are viewed as a good thing and the in-depth quality of repairs is still, in 2020, not measured.
When these insurance companies are working with a repair industry that values throughput and volume it is not surprising that 5 star rated cars are leaving the repair shop with their rating compromised.
In the unregulated world that we work in the insurance companies are probably the best positioned to insist on a proper repair but the huge emphasis on cost is preventing them from doing this.
There is an irony here; the same company that from one department contributes to the IIHS is from another department rewarding repairs that take that 5 Star car to a 3