This recent talk of seat belts in buses (I think Steinn mentioned it recently, but I won't dig up the link) reminds of a good article on vehicle safety in Physics Today which appears available to all.
In particular, the figure which shows acceleration with and without different types of seatbelt very informative. This is the kind of information that is very relevant to students and quite understandable even at the introductory level.
The figure really brings home the point that acceleration (ie decceleration) kills.