The new route, effectively a bypass for Harthill, was to form the first of a 20 miles of the motorway that was considered as important to Scotland’s infrastructure as the Forth Road Bridge.
Around 55,000 cars are recorded using the Harthill stretch of the motorway every day but it is not the busiest part of the road.
The heaviest traffic, on average, is at junction 15 north of the Kingston Bridge where around 119,000 cars move across 10 lanes.
As the M8 grew, construction in the centre of Glasgow from 1968 demanded that huge areas of tenement blocks and business premises were flattened to make way for the motorway.
While the road led to the demolition of swathes of sub-standard properties, response was mixed with major upheaval around St George’s Cross and Anderson taking its toll as the giant roads were created.
Planners created routes that could accommodated car flows of the future. Some 120,000 cars were planned for in some places when, at the time, only 20,000 vehicles were on the road.
As experts have commented, a lot of justification was required with plans for even more motorways around Glasgow shelved over time.
The city centre section was completed in 1972 with the majority of the route finished by 1980.
The M8 was named in 2007 as the worst commuter route in Britain when 85 percent of drivers faced a delay at peak times.
The RAC has recorded that it is the least efficient motorway in the UK with an average speed of just 53mph.