2.
The pilots I worked with in the aerospace industry were willing to put on almost anything to keep them safe in case of a crash, but regular people in cars don't want to be uncomfortable even for a minute.
Nils Bohlin
4.
I realized both the upper and lower body must be held securely in place with one strap across the chest and one across the hips. The belt also needed an immovable anchorage point for the buckle as far down beside the occupant's hip, so it could hold the body properly during a collision. It was just a matter of finding a solution that was simple, effective and could be put on conveniently with one hand.
Nils Bohlin