General Road and Highway Discussion

[SammyOES]

You still want apples and oranges though.  Not all of their national population uses the roads.  So if you include the people that don't use the roads in case 1, it makes sense to me to do the same thing in case 2.

Emphasis mine. I mean, people driving less or fewer people driving seem like completely sensible ways to get to Vision Zero.

Sure, I agree. But the point isn't whether the metric is a good one in a vacuum, just about the best way for the Region to calculate a metric comparable to the one from Sweden they're using.

You shouldn't include the total possible population in one case and not the other. In both cases you're going to have a percentage of the population that doesn't use the roads you're looking at. The fact that there are likely significantly different usage rates doesn't mean you should use a different methodology for calculating the metric. It means you should probably use a different metric altogether (or much better, a set of different metrics).