The issue is you don't define "safe for all" and instead twist its meaning to suit your argument.  How about we make 100% sure that cars are safe for all from meteor strikes? Titanium reinforced armored shells and shockwave resistant construction will do the trick.

When you start talking about "mandatory" you have to do cost-benefit analysis. Automatic braking systems are great if you can afford them, however presently such systems costs thousands of dollars. By suggesting mandating them, you are also effectively denying access to cars (due to lack of affordability) to significant % of population. Consider this before knee-jerk "think of the children" posting next time.