The seat back weighs 30 pounds, in a 20g impact the seat back bolts and lower mounts and frame need to hold 600 pounds.
In that same accident the 200 pound driver seat belt needs to hold 2000 pounds spread over the three anchor points and the webbing stretch.
Both of the scenarios are not that hard to manage. Is a more serious accident say 50g or worse things get far more serious and often not survivable.
Last edited by showkey; 03/26/2017 2:23 PM.