They're suprisingly rugged. Somewhere I have a video of one rolling about six times. The front window popped out (intact) and of course the car got dented up all over, but nothing caved in. It's an early unibody, I'd put it up againt any modern compact car in a collision. They're small, but not unsafe, at least not in my book. Now, some oblivious soccer mom plows over me in her H2, and I'm done, but the same could be said if it happened while I was driving my Explorer.
-S