M1 motorway the A5, the motorway takes a more northerly route through the East Midlands, via Leicester, Loughborough, Nottingham to Sheffield, where the M18 splits from the M1 at Junction 32 to head to Doncaster. Originally, the M1 was planned to end at Doncaster but it was decided to make what was going to be the "Leeds and Sheffield Spur" the primary route with the section to the A1(M) south of Doncaster given the separate motorway number M18. From Junction 32, the motorway passes Sheffield, Rotherham, Barnsley and Wakefield, reaching the original end of the motorway at (the original) Junction 44 to
M1 motorway (Republic of Ireland) route E01. Almost the entire length of the N1 has been upgraded to motorway standard and is designated the M1 motorway. It runs from the Junction 3 of the M50 ring road in Dublin, past Cloghran, Swords, Balbriggan, Drogheda and Dundalk before ending at Ballymascanlon north of Dundalk. It by-passes many towns through which the N1 travelled. The original N1 route now forms the R132. At Ballymascanlon, it becomes the N1 dual carriageway and continues to the border with Northern Ireland. The motorway section of the N1 uses the M1 designation. Small yellow route markers along the motorway route also