In a severe crash, upon occasion, a passenger (or driver) will be restrained by a seat belt well, but sudden deceleration can be so sever that the g-force will actually tear the heart from its arteries. I propose replacing the nylon belt with a blend of nylon, spandex and kevlar, designed to stretch a small amount under load. In a severe crash with rapid deceleration, the belt could stretch to effectively lower the g-force on the torso somewhat. Obviously, this difference would only save a few people-- most would either have been fine with the standard belt or else would die regardless. But right at the margin between, some lives would be saved, at no negative cost to everyone else, other than perhaps monetary. Consider though that all sedans now have interior hatch releases for the trunk, which save very few lives indeed, installed specifically to prevent those saved from dying-- at a significant cost.
-- hulot, Oct 29 2016

Seatbelts already do this. http://auto.howstuf...vices/seatbelt2.htm
[MaxwellBuchanan, Oct 29 2016]

This happens because "loose" seatbelts, with pretensioners, allow the occupant to move forward until stopped by airbag and/or belt.

A proper 5-point race or rally harness prevents this. Completely.

Those who value confort, convenience and appearance more than functionality and efficiency do not deserve to live; therefore, this is a bad idea [-].
-- 8th of 7, Oct 29 2016


I generally find that just not driving into other things at high speed generally works for me, [8th].

As for a slightly-stretchy seatbelt - I suspect that the small amount of stretch in current seatbelts has been chosen as the best compromise between rapid deceleration caused by the belt, and the risk of the person hitting the dashboard or steering wheel.

In other words, I think this idea is already implemented, close to optimally, by current seatbelts.
-- MaxwellBuchanan, Oct 29 2016


// not driving into other things at high speed //

What's the point of having something that goes very, very fast unless you use it to play extremely dangerous games involving an extreme risk of lethal high-speed impact ?
-- 8th of 7, Oct 29 2016


I didn't say you shouldn't play extremely dangerous games involving an extreme risk of lethal high-speed impact; I simply suggested that the rules of the game allow you to not, in fact, suffer such impacts.

High-risk strategies are best if you always win.
-- MaxwellBuchanan, Oct 29 2016


Oh, and, from the <link>:

"Additionally, the seatbelt webbing is made of more flexible material than the dashboard or windshield. It stretches a little bit, which means the stop isn't quite so abrupt. The seatbelt shouldn't give more than a little, however, or you might bang into the steering wheel or side window. Safe seatbelts will only let you shift forward slightly."
-- MaxwellBuchanan, Oct 29 2016


At age 17 (about 35 years ago) I was standing in a bus in Jerusalem stuck in traffic inside an intersection, when a green Opel came directly at us from the side, showing no intention to stop, and slamming directly into the bus. Its hood which closed towards the driver went flying open and hit the large scenic window breaking it to smithereens, right in front of my face, none of which hit or hurt anyone (It was then that I understood why buses are made from heavy duty metal).

Two paramedics yelled: Let me out I'm a paramedic, and a doctor on the bus joined them. An ambulance two or three cars in back worked up its siren and stopped nearby. The driver was already being treated when they brought over the electrodes and started giving him two or three shocks. They then whisked him away, and the doctor coming back onto the bus to the clapping of us the observers explained that the crash had saved this man's life from a heart attack he had before entering the intersection.
-- pashute, Oct 30 2016


That is a remarkable story, [pashute].

There was a similar case in Huddersfield a few years ago, where a man had his head bisected by a sheet of glass falling from a building under construction. It was only the bisection that allowed doctors to notice the massive glial cell carcinoma. 'Course it didn't help him much.
-- MaxwellBuchanan, Oct 30 2016


Fate can be sooooo capricious at times.
-- 8th of 7, Oct 30 2016



random, halfbakery