Cost versus benifit, thats all it comes down to. For all intents and purposes anything is possible if you want to pay for it.
Sadly true and - leaving aside negligence - lives are pretty cheap in the big scheme of things.
Two tales I heard from a chum who used to work for London Transport who ran the 'buses and the Underground (Subway).
The brakes on the 'buses were adjusted to the minimum effectiveness that was legal. The logic was that it's better (read cheaper!) to run over a child than damage 50-odd passengers in an emergency stop.
"Safety Improvements" on the Underground were costed against a theoretical cost of - IIRC - £1M per head. So if a proposed improvement that would save one life a year cost £900K a year to implement - it was done.
If however, it cost £1.1M per year - then guess what??
