Road design, safety and Vision Zero

[plam]

It’s such a weird view.  Even if we keep narrowing down what you’re talking about, it’s still easy to show that you’re wrong.  Bridge designers know that there’s some probability that someone will jump off their bridge and kill themselves.  In aggregate, they absolutely know for sure that people are dying from their designs. And yet, we don’t strive to make it impossible* for someone to commit suicide.

It’s the same with road designs.  Any given stretch of road has some probability of a fatality.  In aggregate, it’s a guarantee someone will die.


* note: we almost certainly don’t do as much as we should.  So I’m not saying we shouldn’t do more - even while still saying we should accept we can never totally prevent bridge suicides.

But we do retrofit pedestrian bridges and build new bridges so that it's quite hard to jump off, with overhanging fences. (Interestingly, this intervention seems to decrease the overall suicide rate as well; when people are deterred, it seems that surprisingly often they just decide not to go through with it after all.)

So the carnage rate on our highways is relatively low and has been decreasing, but it's still quite high because people spend a lot of time on the highways. We do try to make efforts to reduce this rate, but I do tend to agree that we're not trying really hard. As an example of trying hard in another domain, I was reading about how Amazon was working on improving shipping timeliness before they rolled out Prime. Every time they missed their deadline they would figure out how not to do that again. We just don't have that level of effort for reducing collision rates.