Protecting your cranium is the goal of Kranium, a new technology developed for bicycle helmets where the crush layer between your head and the outer shell is constructed from interlocking corrugated cardboard ribs. Don't scoff, the material is extremely strong and the structure of the ribs was shown to absorb 4 times the impact energy as a standard cycling helmet. Unlike polystyrene which loses its effectiveness after one impact, the cardboard has been proven to pass impact tests 5 times in succession.
Another benefit is fit, where expanded polystyrene helmets must use all sorts of pads or straps to customize fit for each individual head, with this method, a user's head can be scanned and a custom template printed for the individual ribs that perfectly conform when assembled. A helmet that fits works far better than one that slides out of position when an impact occurs. Also, once scanned, if you do hit the helmet and want to replace the crush layer, the company can just replace the ribs for your custom helmet using the scanned measurements from the initial fitting.
Since the interlocking rib structure is very light, overall weight is held to a minimum.
Helmet technology seems to advance slowly; better aerodynamics, flashier graphics, faceshields easier to replace, but we've had polystyrene impact layers for quite a long time. Though this project is directed at bicycle helmets I see no reason it couldn't apply to some scooter or motorcycle helmets, too. Will any company look at this and adapt it for applications beyond bicycles?
A light shell, a cardboard layer for protection and a very light liner of some sort, with a nice graphic outer shell, no one will know the difference. No, it won't replace a $500 full face helmet, but it's far better than no helmet at all and maybe better than some currently out there. Interesting to think about.