A guy on a scruffy bike
/thread. There's your answer.VERY SIMPLE ANSWER
Cushioning designed for a single impact will absorb more energy than cushioning designed for multiple impacts
Due to the velocity of a bike impact, you need more cushioning. To do this with reusable cushioning, such as polyethylene or polyurethane, you would need a much thicker cushioning - several inches thick
I'm a packaging engineer, I design reusable cushioning for a living - I'm typically using 2 to 4 inches of reusable foam for a typical 24" to 48" drop.
That's if you drop it with something in it. If it's empty, then the EPS is not affected, and the only question is whether the impact might have damaged the integrity of the hard outside shell.Helmets have something known as EPS which
This thing works only once, so even if you manage to drop your lid on concrete/asphalt from 3 feet or above, your helmet is a goner the EPS has done its work and is of no use in case of an impact.
Helmet Performance: Blowing the Lid Off - Motorcyclist magazine