Any question answered...

Too many cars these days are focused on protecting people in the event of a crash, leading to the weight increasing. Today's "superminis" are 1.5-2 times heavier than their counterparts from 20 years ago largely for this reason. Extra weight means less maneuverability and much longer braking distances.

By trying to protect people in the event of a crash, they're making crashes more likely to happen. This is without taking into consideration the fact that people will be less worried about the outcome of a crash if they feel like they'll be safe in the event one occurs (SUV drivers, i'm looking at you).

See John Adams' work on risk compensation passim.

Seeing as RTCs have consistently declined over the last forty years and there are so many other factors in this, it is hard to pin down statistically.