Entertaining (at least for me) physics discussion of why the problem with SUV/pedestrian accidents isn't due to the mass difference relative to sedans but the height of the SUV. SUV/sedan collisions are a different matter.

https://docs.google.com/document/d/1nERuJylCqR42irULLTVOMjIefb4yD63FI4yLpJpnO4A/edit