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) read N1. The motorway was built in several stages as short disconnected bypasses, replacing the original N1 route. The first section opened (in 1983) was from Whitehall to Coolock Lane followed (in 1985) by the "Airport Motorway" between Whitehall and Dublin Airport, only the third section of motorway opened in Ireland. 1980s style direction signs were still intact on this route up until 2006. Part of this original M1 is now a spur to Dublin Airport, while another part between Whitehall to the Port Tunnel portals is now narrowed to two+one lanes (although still grade separated) as a result of