Road design, safety and Vision Zero

[SammyOES]

It's an understanding of fatalities as a parameter in the design, and if you set fatalities = 0, the design doesn't work. Instead, the approach should be that we have to engineer a solution to a problem (intersection, for example) - how now can we engineer it safely? I'm adding a stop light, what does that mean for safety? I'm adding a left-turn lane, what does that mean for safety?

My problem here is that there is generally no design that actually accomplishes fatalities of 0.  Why?  Because we, as a society, don't actually believe safety should be the only consideration.  Practicality matters.  And to have a design that really, truly, guarantees 0 fatalities (to something like the same level of confidence of a bridge collapsing due to load factors) would make our current transportation system (and by extension our quality of life, economy, etc.) grind to a halt.

So "zero fatalities" is great as a high level goal and guiding principle.  It's garbage if you want to treat it as an actual hard engineering constraint. [And, I'll note again that literally nowhere in the world that I know of, including Sweden, is anyone actually treating this as a hard engineering constraint].

This type of thinking already exists in engineering in terms of efficiency. Efficient traffic movement is a primary variable that they are designing for and constantly trying to improve. Safety is a secondary variable that they need to keep within an acceptable level.

I disagree with this premise that safety and efficiency are treated fundamentally differently.  Both are variables that are bring optimized and kept within acceptable levels.  Now, we can certainly argue that the trade offs being made now aren't the "best" ones.  And in that aspect, something like Vision Zero is great.  Bringing awareness to the trade offs and pointing out that maybe we're siding too often on efficiency and not safety.