When I was younger and didn't have good judgement, I used to work on the RX-7's and took one I built and modified to 120 mph..I cringe when I look back at that, because in 2002, in PA, I drove over the crest of a Hill to see two cars, one a RX 7, that had just suffered a head-on collision.
"The police and paramedics will handle it", I thought, as I glanced at the cars and started to go around the scene....but there were no police! and no paramedics! and no onlookers!
I was literally the first car on the scene..
The carnage was incredible and tragic. In retrospect, I wonder why I didn't panic, because there were several fatalities, resulting from two teens in an RX 7 trying to pass another car who then hit a Corolla with an elderly couple head on..I didn't do anything partcularly brave except have the presence of mind to find my cell phone..
After that incident, I never had a great feeling about small cars. I know they design them with crumple zones and airbags, but when I looked at the poor driver of the Corolla with the steering wheel in his chest, I always felt that the superior size, mass and structure of a heavier car was always a safety factor that was most important..
Obviously a lot of physics and math and engineering go into making this judgement.
But for my money, I still try to make my kid take my 300D or Volvo out on longer, more crucial trips..I don't know, perhaps the Corolla with its airbag is actually a safer car....but intuition says that curb weight and physical dimensions and seatbelts are the best. Both of these cars are relatively 50% heavier and bigger than the Corolla...