Funny enough the correlation between speed and traffic fatalities doesn't seem to matter that much. Speed limits on the German Autobahn are famously much higher but there are fewer fatalities per mile traveled. I'm inclined to believe that the reason is that traffic there and in northern Europe in general is in fact much more orderly then traffic in the US. No overtaking on the right ever. Cars only move into the left lane to overtake somebody. That requires a lot more lane changes, but they are very predictable lane changes and the is so much less to watch it for. People also accelerate properly before entering the Autobahn. So your speed delta to cars in the land you are trying to merge into is usually quite low.

It also takes many hours of driving with a trained driving instructor and a full hour practical test plus a genuinely hard theoretical test to get a license.

Edit: I grew up in Germany and when I moved to southern California traffic terrified me. It was much slower than traffic on the Autobahn but the chaos was just terrifying. Oregon traffic is super slow but still pure chaos compared to what I've experienced anywhere in Europe.