What do pretensioning systems do in the event of a crash?

Pretensioning systems are designed to enhance the effectiveness of seatbelts in the event of a crash. When a collision is detected, these systems rapidly pull the seatbelt tighter against the occupant's body, minimizing any slack. This immediate tightening helps to secure the occupant in their seat firmly, reducing the risk of injury by ensuring that the seatbelt is properly positioned across the body during impact.

This is crucial because in a crash, movements occur very quickly, and any slack in a seatbelt can allow the occupant to move excessively, increasing the chances of injury. By quickly eliminating that slack, pretensioners improve overall passenger safety.

While the other choices involve various safety features in vehicles, they do not specifically address the role of pretensioning systems in securing seatbelts during a crash.