Roads in Northern Ireland
The main roads in Northern Ireland are signed "M"/"A"/"B" as in Great Britain. Whereas the roads in Great Britain are numbered according to a zonal system, there is no available explanation for the allocation of road numbers in Northern Ireland, though their numbering is separate from the system in England, Scotland and Wales.
In Northern Ireland, DfI Roads is responsible for all 25,792 kilometres (16,026 mi) of roads. Road users also have the Highway Code for Northern Ireland, which provides guidance on the legal aspects of driving on Northern Ireland's roads.