[Aloha]

The 59 GM Full Sizes with an X frame did particularly poorly in overlap crashes - it would have performed better with a full head on - or a slimly later one with a permitter frame.

[Doxin]

Most cars do particularly poorly in overlap crashes. It's why those get tested specifically. it's harder to absorb than a full overlap crash.

[bbarn]

It's also a more likely type of crash to occur. Not many cases where one would square off the hit straight on, I'd imagine rather most cases at least one occupant is trying to avoid the crash by moving to the right.