The N3-N4 link route proposed by Transport Infrastructure Ireland (TII) would turn the roads in Dublin 15 into “a massive car park every day”, it has been warned.

Cllr Paul Donnelly (SF) has criticised the scoping document, which puts forward several preferred routes – including a link road to the M50 cutting straight through D15.

He told Dublin Gazette: “The TII have put forward 11 options, with some going down Blanchardstown Road South and at Littlepace/N3 bridge at Barnwell alongside St Catherine’s Park across the Liffey Valley to the N4.

“The scoping document is in relation to major incidents on the M50 and how they would redirect tens of thousands of cars along this N3-N4 link road.

“TII’s options for the M50 link road through Dublin 15 are completely unacceptable. This would massively affect the communities in Ongar, Littlepace, Hartstown, Huntstown and Clonsilla, and would turn our roads into a massive car park every week day,” he said.

Rumblings about the road linking the N3 from Ongar to the N4 outside Leixlip with a bridge spanning Liffey Valley, Royal Canal and the Maynooth rail line have raised hackles from the outset.

Cllr Donnelly warned that a link road to the M50 in D15 would become a rat-run for toll dodgers, and reiterated that “virtually every single councillor” is opposed to any route running through or adjacent to St Catherine’s Park.

He added: “The existing routes would be completely unable to cope with such a massive increase in traffic. It is acknowledged that many of the existing roads are unsuitable and are already at capacity.

“We have two major developments – Barnhill and Kellystown – along with many other significant sites in Clonsilla that will contribute thousands more vehicles to the existing road infrastructure.

“The proposed routes at Littlepace/N3 bridge would also be directly adjacent to the new schools in Barnwell and between the new estates including Blackwood, cutting them off from their commercial and community facilities.

“We need to protect the Liffey Valley from this road. I support the route for the Metro West link, as this is a vital public transport route.

“However, this route would seriously damage the Liffey Valley as an amenity for future generations,” said Cllr Donnelly.