The most important figure to monitor though is not mortality/car-distance, but traffic mortality/population. Let me rephrase that in plain English. Care about creating a safer car driving environment, but care even much more about your loved ones surviving traffic in good health.
In addition to lowering mortality/car-distance, one can reduce traffic mortality/population in two significant ways: shifting traffic from car to safer means of transport, and lowering total car-distance. This holds true both on individual and society level.
I'm going to deliberately provocate now by comparing to a very sensitive number. Just hoping it will wake up at least someone.
Improve road infrastructure safety to Dutch standards? Prevent over four 9/11's per year (12850 deaths).
Improve transportation culture to Dutch standards? Prevent up to eight 9/11's per year (24007 deaths).
Certainly not. We keep track of statistics by vehicle-mile for a reason.