According to Wikipedia:
Crashworthiness is the ability of a structure to protect its occupants during an impact. This is commonly tested when investigating the safety of vehicles.
The OED online gives:
The quality in an aircraft or motor-vehicle that makes it safer in the event of a crash. So
Its first quotation is from the Journal of the Royal Aeronautical Society in 1948. Interesting that three of the OED's four quotations put crashworthiness in inverted commas.
A quick Google search brings up a publication called the International Journal of Crashworthiness - what a great title. It dates back to 1996.