By how much can helmets reduce the number and severity of head injuries in crashes under 30 mph?

Helmets play a crucial role in protecting motorcyclists' heads during crashes, particularly at speeds of less than 30 mph. Research has shown that wearing a helmet can reduce the number and severity of head injuries significantly. Specifically, helmets are effective in reducing head injuries by approximately 50%. This is attributed to the design of helmets, which include features such as impact-absorbing materials that cushion the head upon impact, effectively lowering the risk of trauma to critical areas of the brain.

The high level of protection offered by helmets is particularly evident in lower-speed scenarios where, although the risk of crashes may be elevated, the impact forces can still be detrimental. Therefore, the answer indicating that helmets reduce the incidence and severity of head injuries by half accurately reflects the protective benefits that helmets provide to motorcyclists when involved in accidents.