NHTSA Roof Crush & Foot Print Workshop
This is basically wheelbase x track width. The presentation was about the specifics of how they determine each vehicles "footprint".
Then it was off to the compliance lab. No pictures were allowed, but the lab's web site has some. Look under standard 216 of this page:
A new Honda Fit was tested (and destroyed) at yesterday's event. Held up pretty well. The standard now requires vehicles under 10,000 lbs GVWR to be able to withstand 3 times their unladen weight while allowing for no more than 127 mm (5 inches) of platen (the rectangular plate used to crush the roof) travel and a maximum force of 222 Newtons (50 lbs) of head contact on the head form (like a test dummy).