The **helmet** is a crucial element of passive safety for drivers and passengers of two-wheeled vehicles, such as motorcycles and mopeds. Its main function is to **protect the head** in the event of an accident, as head injuries are one of the leading causes of death in these incidents.

- **Protection against abrasions**: In a fall, the helmet helps prevent the face and head from burning or suffering abrasions when dragged along the pavement. This is especially important because direct contact with the ground can cause serious injuries to the skin and tissues.

- **Impact distribution**: The helmet is designed to distribute the force of the impact across its entire surface, preventing it from concentrating on a single point of the head. This reduces the risk of serious injuries.

- **Importance of fit and fastening**: For the helmet to be effective, it must be well-fitted and fastened. A poorly fitted or loose helmet may not provide the necessary protection in the event of an accident.

In summary, the helmet is essential to **prevent facial and head abrasions** when dragged along the pavement, making it an indispensable element for motorcyclist safety.