IT was billed as the first real motorway in Scotland - and it opened 50 years ago this week.

News reports said it was as important in Scottish communication history as the Forth Road Bridge, opened two months earlier.

The new road that drew so much attention was just over four miles of the Harthill bypass, declared open on November 20, 1964, by the Minister of State, Edinburgh MP EG Willis.

The road was to be the first section of 20 miles of a the new M8 motorway planned to replace the existing A8 road between Newhouse and Newbridge.

The M8 would in time encompass the colossal new Kingston Bridge as well as the Charing Cross Inner Ring Road, a development that changed the centre of Glasgow for ever.

The last part of the motorway within Glasgow was completed in 1980.

Today, the M8 stretches for 60 miles between Scotland's two main cities, except for a six-mile gap between Baillieston and Newhouse.

Stuart Baird, a civil engineer behind the authoritative Glasgow Motorways website, calls the M8 one of Scotland's most important roads.

It transformed vehicle travel across central Scotland, and provided a safe and reliable route.

The 1960s was a time when planners looked ahead and began work on a network of motorways. Car ownership was rising, and planners recognised the importance of freeing old residential neighbourhoods from traffic.

Some parts of the old A8 were unsafe. It had three lanes, with a shared overtaking lane, and the high number of fatalities and serious accidents made it clear something more than upgrading was needed.

"In Glasgow there was a massive building programme for a good few years," Mr Baird said. "There were even plans for more motorways, which, however, were cancelled.

"The motorways were designed for traffic flows that were 20, 30 years in the future. Flows were projected as far as 1990 or 2000, which at the time was unknown in forward planning.

"The planners were thinking ahead, but this made it difficult to justify the new motorways. People asked them, 'Why are you building this new eight-lane motorway at Townhead?'

"The planners said the motorways would eventually get up to 120,000 vehicles a day, but the reply came back: 'Well, we're only getting 20,000 a day at the moment.' Needless to say, a lot of justification was needed at the time."

Glasgow now has some 50 miles of motorway within its boundaries. The Kingston Bridge, of course, is a key part in the M8.

"Since the opening of the M74 completion in June 2011, the Kingston Bridge has levelled out at 165,000 vehicles a day," said Mr Baird. "It can flow freely with up to 120,000 - that was the point of its five lanes. With 160,000, that's obviously where you get the congestion."

Glasgow's motorways allowed pedestrianisation of Sauchiehall Street, Buchanan Street and Argyle Street, Mr Baird said.

"Before then, they were the main east-west and north-south routes through the city centre. Bypassing the centre allowed these shopping areas to be taken out of that equation … The motorways have ultimately created a nice environment in these streets."