I'd assume that a large part of the data that makes up the "mile" portion of the passenger per mile is large trips. So, look at traffic deaths in some dense ci

I'd assume that a large part of the data that makes up the "mile" portion of the passenger per mile is large trips. So, look at traffic deaths in some dense cities and you will probably find much larger numbers than you'd expect. As a quick check of this idea, looking at "vehicle passenger deaths atlanta" in a search gives numbers around 100 for many years. (And Atlanta isn't that dense, all told.)