I used to drive upcountry on these roads. Overtaking on these trunk roads is a big challenge... you have to time your overtaking well, don't overtake on bends or before a rise, estimate the time and distance before the oncoming car approaches, and know your car's power and acceleration well. And never speed excessively, especially round bends because you never know whether there's a car overtaking in the opposite direction.
These skills are now all lost because a generation of folks have grown up driving on the dual carriage NS Highway.