The **seat belt** is a crucial element of **passive safety** in vehicles. Its main function is to protect occupants in the event of an accident, preventing them from being displaced from their seats or ejected from the vehicle. This is fundamental to reducing the risk of serious injury or death.

- **Effectiveness of the seat belt**: Wearing the seat belt correctly fastened **doubles the chances of surviving** an accident. Since its implementation, there has been a significant decrease in traffic accident fatalities.

- **Proper use**: For the seat belt to be effective, it must be well adjusted to the body. The **chest strap** should pass over the collarbone and the center of the chest, while the **lap belt** should be placed over the hip bones, below the stomach. This ensures that the belt functions correctly and minimizes the risk of internal injuries in the event of an accident.


- **Mandatory use**: All occupants of a vehicle equipped with seat belts must use them, both in the front and rear seats, on any type of road. This reinforces the idea that the seat belt is essential for the safety of all passengers, not just those in the front seats.

In summary, the use of the seat belt is vital to halving the risk of death or serious injury in a traffic accident, making the statement that the seat belt significantly reduces the risk correct.