A better metric is deaths per unit of distance travelled. I don't have the numbers, though.
I disagree, a car with 4 passengers is going to have far more deaths per billion miles than a car with 1 passenger, but the risks per passenger is about the same.
That’s why people use deaths per passenger mile to compare things.
In road traffic there are maybe 50 deaths per year per million people (wild guess, but not that far off). With trains in Europe, it's not even 1 per year per million. I don't have to think about all the "almost-accidents" that are part of road traffic. This does come with a price, but buying a newer and safer car also comes with a price.