In the US, most motorists are going 55-65, swerving across lanes in tractors with tinted windows, and have never heard of leaving the left lane to faster moving

In the US, most motorists are going 55-65, swerving across lanes in tractors with tinted windows, and have never heard of leaving the left lane to faster moving traffic. Also, the way most of America is laid out, every trip, even 'local' ones, has a freeway leg, so there is constant merging on or off. Without blinking, of course. In Continental Europe, freeway traffic is much more predictable. Another thing is, Amsterdam to Nice can be driven overnight, on mostly empty freeways. And last, your manager was likely exaggerating grossly. Amsterdam to Nice at 120 avg., would take only about 7hrs 30 minutes door to door (Or Sea to Shining Sea). With 3 kids, that's more like the time spent at rest stops along the way.