Principle of helmet protection

Bicycle helmets work by absorbing the impact of collisions. In short, the inner foam layer inside the helmet cushions the impact of the collision on your skull. Traditionally, many bicycle helmets are made of EPS (expandable polystyrene) foam. Once the EPS foam is crushed and deformed in an accident, it will be irrecoverable and no longer have the ability to absorb the impact of the collision. EPP (Expanded Polypropylene) foam can recover after being impacted, but its ability to absorb impact is far less than EPS foam. GM’s GeCet is also a foam material widely used in bicycle helmets. It is actually a stronger type of EPS foam that is less prone to cracking.