The National Roads Authority in Ireland's "rolling out" quite a lot of those "1+2" roads.. A lot of our newer N-Roads (national primary routes) are wide single carriage way with wide hardshoulders. They're just redesigning the lane layout and installing a centre crash barrier along the entire route. The extra lane alternates from side to side every few KM to allow cars to pass safely, but it's impossible ot pass (due to the crash barrier)when there is no passing lane.
The idea is to eventually completely eliminate all single carriage way roads and hopefully any chance of headon collisions which are almost always caused by dangerous overtaking on single carriageways.
