There's a bunch of old U.S. highways that now have guard rails. Going-To-The-Sun Road in Glacier National Park, Montana, had just a piled rock wall, which is the same as no guard rail, and one-lane narrow in a lot of places, so construction has been widening it and rebuilding the rock walls as concrete and steel reinforced constructs.
Thinking back many roads had no guard rails, some just those useless cables on posts. Of course we didn't text, brush our hair, or drink coffee. We paid attention to our driving.
It's complacency. As cars became safer, idiots became more complacent about paying attention to their driving.
Well guys and girls been on the road for 2 weeks now and got stuck in traffic this morning on Loveland pass