When I was in Sweden on vacation, I was surprised that almost all except the most minor roads have a central divider. To allow overtaking, they have 2+1 lanes, and then after a few km they switch to 1+2 lanes (extra lane in the other direction).

This eliminates the most deadly accidents (head on collisions) and makes overtaking completely stress free.

It's a simple intervention that you can do almost anywhere, and it saves lives immediately. You only need to invest a bit in concrete barriers and paint.

I wonder why almost no other country does that.