The road from Dublin to Galway is around 200 kilometres long and uses the M4 motorway for the first 60 km, and the M6 for the remainder. The M6 starts at the M4/M6 divide and heads west.
The old N6 used to pass through a series of Dublin commuter towns such as Rochfordbridge and Tyrellstown until a dual carriageway was opened in December 2006 as far as Tyrellstown, and Kilbeggan in May 2007. More dormitories were next such as the infamous Moate, before the road finally reached the large midlands town of Athlone. This section was replaced by a new dual carriageway in July 2008. In September 2008, the new dual carriageway sections were all designated M6 and were subjected to motorway conditions.
Athlone was bypassed with a cheap grade-separated dual carriageway way back in June 1991, replacing a detour through the town's winding streets. To ever make this a motorway, some work would need to be done to improve the short ramps, and possibly add weaving lanes. The bypass is riddled with 6 interchanges even though it's only 9 kilometres long. Sure enough, the bypass was left as a dual carriageway in the motorway redesignation round that was implemented in August 2009. There is no timeframe for an improvement, if indeed any will ever occur.
The old N6 gets progressively quieter as one continues further west. It winds it way down to the town of Ballinasloe, squeezing over a bridge and an S-bend, before starting its long lonely journey southwest to the distant town of Loughrea. From there, it covers around the same distance again before finally reaching the outskirts of Galway.
A long time ago, the N6 (or T4 as it was then known) took a more direct route from Ballinasloe to Galway, heading directly west via Athenry. This road is now only a minor regional called R348. Work on completing the new M6 alignment of the N6 was finally brought to a close on 13th December 2009. The Athlone-Ballinasloe section, including a bypass of Ballinasloe, had been first, in July 2009. The long Ballinasloe-Galway section followed a few months later, bringing the Dublin-Galway journey time (from outskirts to outskirts) down to below 2 hours. The new road does not parallel the old N6, but instead follows the even older Athenry route. It is also noteworthy that the last section, specifically the part from Galway to west of Ballinasloe, is tolled.
In the outskirts of Galway, the N6, both existing and future, ends in the townland of Rosscam. The existing route intersects the north-south N18 Galway-Limerick road at the town of Oranmore before using a new dual carriageway route built in the 1990s to enter the city from the north. The new route, not a motorway but a dual carriageway, will end at the townland of Doughiska but a bypass will skirt the city to the north further out, before finally coming to an end at the N59 northwest of the city. This represents a scaling back of the original route which would have terminated west of Barna on the coast a long way to the west of the city. However, the missing Doughiska-Barna piece is going to be built by Galway City Council as a regional project.
The bypass is controversial as it will likely sever the Gaeltacht suburb of Menlough and other areas from the rest of the city. This and other issues have delayed it by years and it was not listed as a part of the interurban motorway network - and therefore was not completed by 2010. Even the scaled back version of the bypass was only granted planning permission in December 2008. However, in April 2013, it was blocked by a European Court of Justice ruling.
As of early 2015, it is back in planning with a preferred route to be announced soon, when consultation is concluded. The new route options all now go as far as Barna west of the city, the part that was previously curtailed. This represents a reset to the original routing.
Today, the emerging preferred route for the new Galway Bypass was announced. The PDF map is here. RTE have details surrounding the plans. I have updated this site's map of the route too. It seems that Galway City Council got their wish and the bypass is quite far from the city centre and the existing bypass. The existing bypass approaches within 800 metres of Eyre Square, the historic centre of Galway; the closest approach of the new bypass will be 2.8 km. The new road is mostly a dual carriageway except for the western end which will have sparser traffic and be single carriageway with roundabouts. In all, the new bypass consists of 10.9 km of dual carriageway and 5.5 km of single.
To the east, the road begins right at the existing terminus of the most recently built parts of the N6/M6 at Doughiska where there is a large roundabout joining the new roads to the current bypass. The roundabout will be replaced with a complex interchange providing access to four roads - the existing and new bypasses to the north, the existing R446 to the south, and the N6 heading east to the M6.
Perhaps oddly, the existing N6 to existing bypass will be the main flow here - traffic arriving from the east will have to turn off to enter the new bypass, and vice versa. This detail alone puts the final nail in the idea that the new bypass might be a motorway continuation of the M6 - if it was, traffic would probably have to pass through lights or roundabouts to continue to the new route. The large new junction features a lot of loops and turning slips which look rather small and tight.
There will be three major junctions - with the N59, the N84, and surprisingly, with the N17. Previously it was planned that the bypass would have no junction with the N17 Tuam Road, partly in order to force bypass traffic onto the M6 and the new M17 which is currently under construction instead. This in turn was because the village of Claregalway is badly in need of a bypass, but none is forthcoming. Surely the new junction with the Tuam Road will now mean that a Claregalway bypass will be essential, since no traffic in the city centre or west of Doughiska will use the M17 to get to Tuam.
In addition, the N17 Tuam Road junction will be a double-junction, also featuring slips to a new distributor road that will link the Parkmore and Ballybrit industrial estates.
Most controversially, the new bypass will feature two tunnels in order to avoid damaging an area of limestone pavement and the Galway Racecourse. However, since the surface cannot be disturbed, this will mean that both tunnels will have to be drilled - an expensive option compared to cutting and covering. These tunnels are both being done to placate opposition and don't make a lot of sense from a practical or cost perspective.
According to the RTE article, there will be around 45 houses under threat of demolition due to the plans. In particular, at the N59 crossover, most of the houses visible in this aerial view will need to be entirely demolished, including a group of new houses called Ard An Locha. This is unfortunate, and emphasises the importance of forward planning for route alignments for infrastructure. Otherwise, a swathe of destruction may need to be cut through an urban area. However, note that the detailed design of the route has not been decided, and the exact pieces of land and property that will be needed to build it are not yet set in stone.
The road between the N6 at Doughiska and the N59 is an 8 km dual carriageway, and probably a high-quality one. However, the dual standard only continues further west another 2.9 kilometres as far as Ballymoneen Road. From here, it narrows to a 5.5 km single carriageway road with roundabouts, but intersections with minor roads all seem to be bridged. In all, there will only be 4 roundabouts along this section, with presumably no access at all in between.
Finally, some guesses as to numbering. Since the existing bypass is only numbered N6 as far as the N59 junction, it's worth wondering if the new bypass will be the same, with the part from the N59 to Barna a regional road. I am assuming the dual carriageway's new junctions will be numbered 20-23, following the existing sequence.
The next steps will be to move to land purchase and design. The RTE article states that Galway City Council intend to submit planning documents early next year before moving to construction in 2017. If this was followed, the road would open by 2020. It does seem optimistic since as of 2015 there is no secure funding available in any case.
A higher-detail map has been made available by Galway County Council.
As a result of the ongoing design process, a new map featuring layout changes has been issued. The main change is to roll up the slips leading to the Parkmore Business Park. East and westbound access to the bypass from the local area is still available.
The latest news on the design of this scheme is that it will be a motorway after all. The junction at Doughiska will flow the existing N6/M6 onto the bypass. The latest design document is here - Doughiska is on page 11.
The scheme is still with An Bord Pleanala (Planning Board) and a decision is not expected until summer 2020.
East Athlone Motorway Services Area is due to open in November 2019.
East Athlone Motorway Services Area has opened to the public after several years in legal limbo due to a court challenge.
A decision on planning permission for the M6 Galway Bypass is due in late April.