I usually always cycle with a rucksack with things I need for the ride inside. I wondering when out earlier whether a rucksack filled with blocks of polystyrene would be beneficial for the back in cases of being hit from behind? Similar to how the polystyrene in helmets make the chances of head injury far less. What do you guys think?
I think it's good idea, the polystyrene will provide protection from the gear you carry in your rucksack.