The Government has been told it has “no other option” but to build a new railway line into Dublin, if it wants to relieve congestion on the M50. 

The road into the capital is the busiest in Ireland but has become a victim of its own success. 

Promising fast access to Dublin, tens of thousands of people have moved into the suburbs in the expectation that they could use it to commute. 

But travel times on the road have surged, as congestion has worsened significantly in recent years. 

“It's particularly the area around the Red Cow, but that saturated zone of the M50 is spreading year by year,” Seán Keyes of Progress Ireland warned on Newstalk Breakfast. 

“Roads by their nature, they fill up, that's just the way things work. 

“All things being equal, people love commuting by car. 

“It's very convenient, but it's convenient until you reach this, roughly this point now where, you know, your journey speed goes from kind of 80 or 90 kilometres an hour to 30 kilometres an hour.” 

Toll booths are seen on the M50. Picture by: Mark Stedman/RollingNews.ie

Mr Keyes added that there “probably is a case for another motorway” around the capital, but noted there are other transport projects that need funding as well. 

“By the standards of other places, risks to the port, all sorts of reasons, it does make sense to have more road infrastructure,” he said. 

“There's a big ‘but’; that ought not be the backbone of our housing and transport strategy. 

“If you just build a motorway and don't build a competing, better piece of transport infrastructure, which we could talk about if we wanted to, what you'll end up with is just a very, very spread out city. 

“The city centre will sort of wither away, commuting times will be much longer and all this sort of stuff that I think most people would prefer we don't have.” 

 An exit road at Junction 12 of the M50 with heavy traffic. Picture by: Alamy.com. 

The Government has forecast that over the next four decades, the Republic’s population could grow to between six million or 7.6 million, depending on the State’s immigration policies and the nation’s birthrate. 

It means, Mr Keyes argued, that the country needs to be “thinking a lot bigger” about infrastructure.  

“Something like electrified commuter rail, which is like a different order of magnitude of capacity,” he said. 

“That would really make a dent in things and kind of a properly fully specced out commuter rail line could move sort of five times the numbers of the M50 in and out of the city every day. 

“I think something like that is justified in Dublin's case.” 

Mr Keyes added that a new railway line would be “absolutely possible”, but would require “huge money” from taxpayers to build. 

“By our calculations, that electrified rail thing would come in around the cost of Metrolink,” he said. 

“It's hard to say, but what it would deliver would be a system that's five to 10 times more extensive, larger, depending on how you want to say it.” 

Despite this, Mr Keyes believes there is “no other option” if the Government wishes to cut congestion on the M50. 

“The do nothing option is you just keep slamming cards into the M50,” he said. 

“And more and more of the M50 turns into a car park and journey times on the M50 go from 80, 90 kilometres an hour to 30 kilometres an hour.

“It's kind of a pick your poison scenario.”

Main image: Queues of traffic on the M50. Picture by: RollingNews.ie.