They are designed to prevent drivers and passengers from being completely ejected from a vehicle by spreading out their bodies’ energy over their shoulders, chest, and pelvis in a collision. Seat belt buckles, do just that, buckle. It has the job to secure as well as release the tongue. The http://pandora.nla.gov.au/external.html?link=https://www.ledteks.com/seatbelt-and-safety-belt-webbing