@psn Do you mean that the distribution of size of roads in the middle of nowhere is shifted towards larger, or that it's bimodal, or something else?
@robryk One guess is safety - having a dual carringeway eliminates dangerous overtaking. Having a higher design speed also means that speeders are less dangerous as well.
Another guess is that it is a motorway, but the current gov doesn't want to build new motorways, so someone in the DoT did s/M/N/ on a bunch of plans.
A 3rd guess is corruption - give taxpayer money to road builders. then the question of demand doesn't matter.
@isomer @robryk A bunch of the vision zero stuff I’ve seen is looking at urban environments. The one advantage of this sort of road is you don’t dump through traffic into little towns and villages. There’s no legal ban on cycling or walking on an n road. In this case, the Waterford greenway is along the river just out of shot.
@robryk Comparing with older N roads (say, the N2 to derry or the N59 in mayo), the older road is single lane each way, and has a lower speed limit (and thus tigher turns etc). They also go through towns etc. My expectation is the newer N roads look like the older. One reason I expect this is cost - 4 lanes presumbly cost twice two lanes.