Inertial seatbelt release

Inertial unlatching & false latching

Inertial unlatching occurs when the seat belt becomes unlatched during a collision, allowing the latch plate to pull out of the buckle. Though the automotive industry denies that a seat belt can inertially unlatch, recent testing has demonstrated how accident level forces can cause the buckle "pawl" or button to depress and release the latch plate. Millions of vehicles have seat belts that are susceptible to this phenomenon.

False latching occurs when the latch plate looks, feels and even sounds like it is latched when inserted into the buckle but is not fully engaged. Minimal amounts of force will cause a falsely latched buckle to completely release the latch plate. When a seat belt is falsely latched or becomes inertially unlatched, the occupant is essentially unbelted and unrestrained and moves as though he or she were never belted in the first place. Such occupants are frequently ejected or found unbelted inside the car.

Though the occupant was properly belted before the seat belt became unlatched, the Police Report will often list the occupant as being unrestrained. Cases involving inertial unlatching or false latching frequently arise when either a surviving occupant insists he or she was belted or when other occupants confirm that the deceased occupant was wearing a seat belt.

References

*http://www.auto-law.com/CM/PracticeAreaDescriptions/PracticeAreaDescriptions10.asp
*http://www.safetyforum.com/inertial/