The history of automotive safety engineering is a reflection of society. As society has changed, evolved, advanced and reassessed its values, so too were those values foisted, painfully, upon automotive engineers.
After little-Suzy-homemaker loses control of her fully-loaded-by-110-pounds-of-groceries shopping cart, will it set off the side airbags on your 2010 Ford Taurus at a speed of 10 MPH? Let's find out.
A lot of times when people see a modern car accident or push on a plastic bumper, they wonder why cars aren't built the way they used to be. Well, a lot of it has to do with human survivability. If you've ever had high school level physics you'll understand the following formula:
F = ((m2 - m1) x (V1-V2)/(t2 - t1))