M80 motorway

The M80 Stepps to Haggs Completion Project connected the two-halves of the current motorway via an online upgrade of the existing A80, passing through Cumbernauld and Auchenkilns, and the offline creation of new motorway from Stepps to Mollinsburn. Although various plans were considered from the 1970s to 1990s[6] to connect the two sections of motorway, it was not until 2003 that a definitive timeline for proposing, developing and executing a completion plan was announced.[7]

Two routes were proposed for development: the so-called Kelvin Valley route, which would create a bypass to the north of the existing line of the A80, and the "online" upgrade of the existing A80 to motorway grade. In October 2005, the project was put to a public inquiry, which ended in August 2006. The Kelvin Valley route was not chosen[8] as it would have breached the Antonine Wall and destroyed the Castlecary Roman fort;[9] instead the online upgrade of the A80 through Cumbernauld was selected.[8]

Originally budgeted to cost £130–180 million,[7] but as of August 2010 was estimated to cost £320 million,[10] preparatory works were started in November 2008, and construction work began in January 2009.[11] The project was completed in September 2011.

The upgrade plans were set into three discrete phases.[12] Phase one involved the creation of 8 kilometres (5.0 mi) of road from Stepps, routing north of Muirhead, Moodiesburn and Chryston, and meeting the line of the existing A80 at Mollinsburn with the construction of a new interchange, connecting the M80 with the M73 and the western section of the A80. Phase two required the online upgrade of the A80 between Mollinsburn and Auchenkilns, with the attendant upgrade of adjoining on-slip and off-slip roads, meeting the Auchenkilns Interchange. The interchange was opened in November 2005 after the online grade separation of the Auchenkilns Roundabout from the line of the dual carriageway created a grade separated dumbbell interchange, linking the A80 (and subsequently the M80) with the A73 and B8048.[13][14] Phase three saw the A80 upgraded online from Auchenkilns to the Haggs Interchange east of Cumbernauld – also seeing some junctions being upgraded, but with some being removed –[15] completing the connection of the western M80 to the eastern M80, and connecting to the M876 and M9 motorways. The M80 crosses the Glasgow to Edinburgh via Falkirk railway line and Forth and Clyde Canal.

County	Location	mi	km	Junction	Destinations	Notes
Glasgow	Glasgow	0	0	1[coord 1]	M8 – Glasgow, Edinburgh
		1.7	2.7	2[coord 2]	B765- Bishopbriggs
North Lanarkshire	Moodiesburn	3.5	5.6	3[coord 3]	A806 – Kirkintilloch, Stepps
		6.9	11.0	4[coord 4]	Moodiesburn, Cumbernauld	No Eastbound entrance or Westbound exit
		7.3	11.8	—[coord 5]	M73 – Gartcosh	No Westbound entrance or Eastbound exit
	Cumbernauld	9.0	14.5	4a[coord 6]	A8011 – Balloch, Cumbernauld	No Westbound entrance or Eastbound exit
		9.4	15.1	5[coord 7]	A73 – Carluke, Airdrie
		11.6	18.7	6[coord 8]	A8011 – Cumbernauld, B816- Castlecary
Falkirk	—	13.3	21.4	6a[coord 9]	B816- Castlecary, Allandale	No Southbound entrance or Northbound exit
		13.9	22.3	7[coord 10]	A803 – Haggs, Banknock
	Denny	15.2	24.4	8[coord 11]	M876 – Kincardine, Falkirk	No Northbound entrance or Southbound exit
Stirling	—	20.6	33.1	9[coord 12]	M9 – Grangemouth, Edinburgh, Dunblane A91 – Cupar, St Andrews A872 – Denny, Stirling
1.000 mi = 1.609 km; 1.000 km = 0.621 mi       Incomplete access

Coordinate list

• List of motorways in the United Kingdom

• Glasgow Motorway Archive - The M80 Motorway
• m80steppstohaggs.com (archive)