It seems that the fatalities per billion vehicle kilometres will be skewed simply by the average trip length being longer in the US. Fatalities per number of tr

It seems that the fatalities per billion vehicle kilometres will be skewed simply by the average trip length being longer in the US. Fatalities per number of trips is probably a better metric since longer trips tend to use safer roads like motorways. It's just not possible to rack up that many "safe" miles somewhere like the UK, while the number of more high risk miles, ie. towns and country roads, is probably more similar. As suspected, that metric is the one the US does the best on in the article linked. The best metric is probably fatalities per capita. It's not fair to take into account only the number vehicles because the whole population is at risk when it comes to cars. And it's not fair to take into account number of miles travelled due to the difference in trip lengths.