M50 motorway (Ireland)
{{UK motorway routebox| motorway= M50
length-mi= 24 | length-km= 40 | direction= North-South (C-ring) | start= M1 motorway near Dublin Airport | destinations= Ballymun, Finglas, Blanchardstown, Palmerstown, Tallaght, Dundrum | end= Bray | opening-date= 1990 (J6-J11) | completion-date= 2005 | junctions= 3 - M1 motorway
17 - M11 motorway.The M50 motorway is a motorway and National Primary Route (N50) in the Republic of Ireland running in a C-shaped ring around the northern, western and southern sides of the capital city, Dublin. One end of the route is located north-east of the city, with a connection to the M1 motorway (running north to Belfast). It crosses the dual West-Link toll bridges over the River Liffey west of Dublin, and loops around south east of the capital to meet the M11 route (running south to Wexford) at Bray, County Wicklow.
The M50 was first proposed by the Dublin Transportation Study of 1971. The completed M50 motorway opened on 30 June 2005. Work commenced in early 2006 on upgrading the earlier sections of motorway, with the current grade-separated signal-controlled roundabout interchanges to be replaced with free-flowing "spaghetti junctions", and much of the road to be widened to three lanes in each direction.
The M50 is the busiest road on the island of Ireland.
The N50 is the only National Primary Route that is entirely motorway (hence apart from on the statutes, the road is designated M50). The non-motorway ring-road following on from the north end of the M50 is not the N50, but rather a separate National Primary Route, the N32.The M50 was originally planned to divert traffic travelling through on National Primary Routes away from the city (a full bypass of Dublin) and it now also serves as an arterial route for Dublin city itself, connecting the various outlying suburbs. Though often viewed negatively by some, the M50 is a victim of its own success and has been responsible for much investment and economic activity in the Dublin area. Its benefit to cost ratio is in the order of at least 10. Thus the upgrades to the M50 will be money well spent.
Each of the National Primary Routes leaving Dublin have junctions with the M50. As of 2005 these are in the form of grade-separated signal-controlled roundabout junctions, not free-flowing intersections. The other primary routes served are the N2 to Derry, N3 to Navan/Cavan/Northwest, N4/M4 to Galway/Sligo, N7/M7 to Cork/Limerick/Waterford, and the N11/M11 to Rosslare. Additional junctions along the motorway serve other suburbs of Dublin such as Ballymun, Tallaght, Dundrum and Sandyford.
Most of these interchanges are subject to notorious levels of traffic congestion, as are the toll-plazas at the West-Link bridge. The busier roundabout junctions are signal-controlled, with tailbacks extending for several kilometers at rush hour. The most infamous is the Red Cow roundabout junction with the N7, also dubbed the "Mad Cow Roundabout". As well as being the junction of two of the busiest roads in the State, the Luas tram line from Tallaght runs level across two slip roads, continuing city-bound in the median of the N7.
The roundabout at the N3 is also notable as the Royal Canal and the Dublin-Sligo railway line pass through its centre.
Due to excess curvature between Junctions 10 and 14 a lower speed limit (100 km/h) is in force for cars. Special speed limits for other vehicles (buses, lorries etc) are unchanged.The M50 motorway consists of two-lane dual carriageway, though auxiliary/weaving lanes are provided at several junctions. Plans are in progress under the National Development Plan to upgrade several of the roundabout junctions, including the Red Cow, to free-flowing grade-separated interchanges. The upgrade project also includes widening the surrounding motorway to three lanes each direction from the M1 to Sandyford with the extra driving lanes replacing the existing wide grass-covered median. The upgrade programme has been planned to include at least three stages – the upgrade of the section between the N4 road and N7 road (along with replacing the interchanges with near-freeflow layouts), followed by upgrading the northern and then southern motorway sections.
Completion of Dublin's ring road by construction of an Eastern Bypass of the city has been proposed. This plan is highly controversial, as it would require a tunnel across Sandymount Strand to or possibly through Booterstown Marsh bird sanctuary. A motorway reservation from Sandyford to Booterstown has been included in the Dun Laoghaire-Rathdown Development Plan, with space allowed for an interchange where it crosses the N11. The Dublin Port Tunnel, already under construction and due to open in 2006, would form the northern half of the Eastern bypass.
Controversy has recently arose over a plan to buy out NTR plc's rights to the West-Link toll bridge, and replace it with a set of electronic tolls on the entire M50 motorway. Concrete details of this plan have yet to be fully announced however.The road begins as the N32 at the Malahide Road in Dublin. It becomes the M50 at Junction 3, which is also Junction 3 on the M1. When the Dublin Port Tunnel opens in summer 2006, the tunnel together with M1 Jcts 2 and 3 will be made a new part of the M50, providing the missing M50 junctions 1 and 2.
{| border=1 cellpadding=2 style="margin-left:1em; margin-bottom: 1em; color: black; border-collapse: collapse; font-size: 95%;"|- align="center" bgcolor="0080d0" style="color: white;font-size:120%;" | M50 Motorway | | Junction | Road or Areas served |
| J3 | M1, N32 |
| J4 | Ballymun |
| J5 | N2 / Finglas |
| J6 | N3 / Castleknock / Blanchardstown |
| West-Link toll bridge |
| J7 | N4 / Palmerstown |
| J9 | N7 / Clondalkin |
| J10 | Belgard |
| J11 | N81 / Tallaght |
| J12 | Scholarstown |
| J13 | Ballinteer/Rathfarnham |
| J14 | N31 / Dundrum / Sandyford (restricted access) |
| J15 | Leopardstown / Carrickmines |
| J16 | Loughlinstown |
| J17 | M11 motorway, Bray/Shankill (restricted access) |
