Screw you both.

Measure butt-in-seat hours.

That doesn’t count people who don’t get in a car wreck, simply because they walked to buy groceries

Aren't we comparing drivers vs drivers here?

If we aren't then you're just measuring the fraction of the population that drives (which is largely a reflection of wealth and demographics) which isn't really a measurement of the safeness of the roads and driving.

We’re talking about people killed trying to move around the place they live. Butt-in-seat hours is a fine way to measure automobile vs automobile stats, but when we’re talking about deaths from transportation, counting only automobile hours is silly. There are various ways to get around a city, and the way you do that hardly matters if it suits the purposes of that trip.