What can activate a seatbelt pretensioning system?

The seatbelt pretensioning system is designed to enhance the effectiveness of seatbelts in the event of a crash by retracting any slack in the seatbelt at the moment of impact. This system is typically activated by sensors that detect a crash event, such as sudden deceleration or changes in the vehicle's dynamics. When these sensors confirm that a collision is imminent or occurring, they trigger the pretensioners to pull the seatbelt tight against the occupant, minimizing movement and reducing the risk of injury.

While other options might seem relevant to occupant safety and comfort, they do not activate the pretensioning system. Manual adjustments or routine vehicle maintenance do not involve any triggering mechanism for crash detection. Similarly, changes in passenger weight are not sufficient to activate the pretensioning system; it is specifically designed to respond to the dynamics of a crash rather than to continuous changes like weight. This ensures that the safety features of the vehicle function as intended during emergencies, providing critical protection to occupants at the moment of impact.