[Xamayon]

Just 'spitballing', but if the restraints are adequate, the compression of flesh may act to slow down and spread out the force of the accident to a certain degree. Bruising may be more likely, and the increased overall force might break ribs and such, but increased weight may have some benefits at some speeds/in some scenarios.

Some possible downsides would be overwhelming the airbags capacity, and larger overall volume of space which needs to be protected from intrusion/crushing/etc. I Wonder how much this has been studied, hard rubber and steel dummies probably don't reflect conditions at the extremes very well...

[tjoff]

That is exactly what the crumple zone in the car is for though. You only have X meters of margin before you need to be at full stop. Assuming (dangerous to assume, yes) it does its job perfectly the most important factor becomes to react, that is to start the slow down as quickly as possible so you can utilize the crumple zone to max effect. I feel like flesh compression will mostly delay the impact rather than properly slowing you down (fast enough), which would be a bad thing.

That is in part also why it is so important to have a properly tightened seat belt and why we have explosives to tighten it up further when a collision is detected.