What does the shoulder portion of a seatbelt need to do?

The shoulder portion of a seatbelt is designed to go across the collarbone and chest to provide maximum protection during a collision. This positioning helps to distribute the force of a crash across the stronger parts of the body, namely the chest and shoulders, minimizing the risk of serious injury. When the belt fits properly, it keeps occupants securely in their seats and prevents excessive forward movement, which can result in injury.

Other options suggest inappropriate usage of the shoulder strap, such as wearing it tightly around the neck, which can be dangerous or allowing it to hang loosely, which would not provide any safety benefit. Adjusting for comfort is important as well, but the primary function remains ensuring that the shoulder strap is properly positioned across the collarbone and chest to maximize effectiveness in crash scenarios.