Although the entire route is colloquially referred to as the M74, for more than half its length, south of Abington, the road is officially the A74(M); see naming confusion below.

From its junction with the M8 just south of the Kingston Bridge, the newest section passes through the Glasgow districts of Govanhill, Polmadie, Oatlands and parts of the nearby towns of Rutherglen and Cambuslang, on an elevated embankment, with junctions at Kingston, Polmadie Road, Eastfield and Tollcross before connecting to the much older section of the M74.

North from junction 4, the E05 takes a short stretch of the M73 connecting to the M8 and then proceeds westwards through Glasgow to Greenock.

The southern sections, where there was no need to bypass the existing route, were not originally upgraded to motorway standard, but to dual carriageway without hard shoulders or full grade separation.

Plans to upgrade the English section of A74 (Cumberland Gap) from the Scottish border at Gretna to Carlisle were announced in 2004.

Construction on the six-lane M74 Northern Extension or M74 Completion Scheme northwards by 5 miles (8.0 km) through the south-eastern part of Glasgow to meet the M8 started in 2008,[7] with opening on 28 June 2011.

[9] The city centre section is supposed to perform a similar role to the never-built southern flank of the Glasgow Inner Ring Road planned in the 1960s, and first set out as a scheme in the Bruce Report of the 1940s, but only half-completed.

Developers mobilised discourses of blight and inflated job claims (which had expanded from 2,900-4,000 in 1994 to 44,000 in 2001) to argue for approval.

The enquiry concluded that the job forecasts were "not [shown] to be robust" and the extension would have "very serious undesirable results", including community severance and an adverse effect on the environment.

[10][11] The scheme was at the centre of a road protest from local campaigners and environmentalists; JAM74 launched an appeal against the original decision to ignore the inquiry's advice, however the case against the road orders collapsed on the first day of the hearing in June 2006, the net effect being a further three years delay to the start of construction, adding an estimated £20m to the construction cost.

[11] Archaeological mitigation was required as part of the project and was one of the largest coordinated series of excavations carried out in an industrial city in Western Europe.

Discoveries included the Govan Iron Works and associated workers' housing, the Caledonian Pottery, a block of 19th century tenements, a biscuit factory, urban limeworks and more.

[10][11] A report issued by Transport Scotland, one year after its opening, found the scheme was achieving its key objectives, including improved journey times and providing relief to the local road network and M8.

[16] Construction of the East End Regeneration Route (designated as the A728) made use of existing stretches of road and filler sections on previously derelict land and has the ultimate intention to connect the M74 Northern Extensions with the M8 motorway at the Provan Gas Works interchange with the M80 motorway.

[17][18] Although plans were approved in early 2016, construction did not commence;[19][20] in 2021, it was confirmed that the project was still under consideration by the council despite funding problems and opposition on environmental grounds.

Meanwhile, the English eight-mile (thirteen-kilometre) section of A74 was not upgraded due to lack of funds, leaving the "Cumberland Gap" of dual carriageway between the three-lane motorways.

[23] When the Scottish Executive was established in 1999, taking over responsibility for roads in Scotland, Sarah Boyack said that "We have no current plans to rename or redesignate the M74 or A74(M) motorways between Glasgow and the border as the M6".