Mechanics of Bike Helmets and How They Are Improving
Bike wrecks happen fast. In two milliseconds—that's one-hundred-times quicker than a blink of an eye—a regular ride can turn into a disastrous noggin-buster.
Collisions can be made up or two types of forces—linear and rotational—but more often than not are a crushing combo of both. Currently, traditional helmets already protect against linear forces with a cushioned yet collapsable exterior that reduces the impact on the skull.
The rotational element are much more challenging to account for. Like the exterior of a traditional helmet, skulls are our natural main brain protection. However, our skulls are buffered by a thin cover of cerebrospinal fluid and then a scalp on top of that, which creates a kind of "sliding layer." This sliding layer is what reduces rotational forces.
Many companies are not focusing on making helmets that will reduce or eliminate rotational forces caused in a crash by mimicking a "sliding layer" within a helmet.