M18 motorway (Great Britain) and 12 June 2015. The M18 was originally to be part of the M1, but it was decided to route the M1 towards Leeds instead of Doncaster, and the routing of what would have been the M1 east of Sheffield became the M18. Data from driver location signs are used to provide distance and carriageway identifier information. The location sequence is a continuation of the M1 location sequence. !scope=col|miles !scope=col|km !scope=col abbr="Southbound"|Southbound exits (B carriageway) !scope=col|Junction !scope=col abbr="Northbound"|Northbound exits (A carriageway) !scope=col|Coordinates M18 motorway (Great Britain) The M18 is a motorway in Yorkshire, England. It runs from the east of
M1 motorway (Republic of Ireland) and 9.4 km south of the border. This allows traffic to flow freely from Dublin Port on motorway/dual-carriageway standard road to the Hillsborough Roundabout, located south of Lisburn. This is Transport Infrastructure Ireland's Exit numbering scheme for the M1. all junctions feature their number on road signs. The upgrade of the N1 is now complete in the Republic of Ireland, the first major route to be completely upgraded to motorway/dual carriageway standard (outside of Dublin city centre) as per the National Development Plan. The Northern Irish authorities have no plans to replace the A1 route (currently dual carriageway) with motorway,