There’s an old saying -- you can’t repeal the laws of physics. That may be the discussion right now at several small-car manufacturers today. The Insurance Institute for Highway Safety, known for its slow-motion car crash videos, sent the Honda Fit crashing into a Honda Accord, the Smart ForTwo into a Mercedes C-Class and a Toyota Yaris into a Toyota Camry -- each at 40 miles per hour. The results indicate what safety you may be trading for efficiency when your mode of transportation shrinks. The tests are called "offset" crashes. The cars crash not quite head on, similar to...