Helmets prevent many of these injuries or make them less serious. Bicycles, even when in the hands of young children, can be rapidly moving vehicles, easily reaching speeds of 20 miles per hour or more. Compared to the dollar and human cost of head injuries, helmets are inexpensive insurance. When a person's head hits the ground, the skull stops short, but the brain continues to travel, crashing against the skull. Helmets are designed to absorb the shock of the impact to prevent or reduce the crash between the brain and the skull.
Helmets can also have bright colors and reflective tape or striping that makes riders more visible.
What You Should Look for when Buying a Helmet. A helmet must be constructed with thick, firm polystyrene or other shock-absorbing material. This crushes on impact to absorb the shock of the fall and reduces the chance of brain injury. The foam pads found inside many helmets are for comfort and sizing. They do not provide crash protection.