The **helmet** is a crucial element of **passive safety** for drivers of two-wheeled vehicles. Its main function is to **protect the head** in the event of an accident, preventing direct impacts against the ground, other vehicles, or road elements. Additionally, it distributes the force of the impact to prevent serious injuries and protects the face and head from burns when sliding on the ground.

For the helmet to effectively fulfill its function, it is essential that the **retention strap is correctly fastened**. This ensures that the helmet remains in place during an accident and does not come off, which is vital for the user's protection. An unfastened or poorly adjusted helmet will not offer the necessary protection and can result in serious injuries or even death.

Moreover, head injuries are the leading cause of death in two-wheeled vehicle accidents, and the proper use of a helmet can save lives. Therefore, it should always be ensured that the helmet is well fastened to maximize its effectiveness in the event of an accident.