Dublin is also the main hub of the country's road network. The M50 motorway (the busiest road in Ireland), a semi-ring road runs around the south, west and north of the city, connecting the most important national primary routes in the state that fan out from the capital to the regions. As of 2008, a toll of €2 applies on what is called the West-Link, two adjacent concrete bridges that tower high above the River Liffey near the village of Lucan. The West-Link Toll Bridge was replaced by the eFlow barrier-free tolling system in August 2008, with a three-tiered charge system based on electronic tags and car pre-registration.
To complete the ring road, an eastern bypass is also proposed for the city of Dublin. The first half of this project is the Dublin Port Tunnel which opened in late 2006 and mainly caters to heavy vehicles. The plan to build the eastern bypass around Dublin has been effectively shelved by the Department of Transport as there are no funds available for the expected €1 billion project.
The capital is also surrounded by an inner and outer orbital route. The inner orbital route runs roughly around the heart of the Georgian city and the outer orbital route runs largely along the natural circle formed by Dublin's two canals, the Grand Canal and the Royal Canal, as well as the North and South Circular Roads.
Dublin is served by an extensive network of nearly 200 bus routes which serve all areas of the city and suburbs. The majority of these are controlled by Dublin Bus ( Bus Átha Cliath ) which was established in 1987 , but a number of smaller companies have began operating in recent years. Dublin Bus had 3408 staff and 1067 buses providing over half a million journeys per weekday in 2004. Fares are generally calculated on a stage system based on distance travelled. There are several different levels of fares, which apply on most services. Certain routes (particularly Xpresso) use a different fare system.
The Dublin Suburban Rail network is a system of five rail lines serving mainly commuters in the Greater Dublin Area, though some trains go even further to commuter towns such as Drogheda and Dundalk. One of these is an electrified line that runs along Dublin Bay and is known as the Dublin Area Rapid Transit (DART) line.
A two-line light rail/tram network called the Luas opened in 2004 and has proved popular in the (limited) areas it serves, although the lack of a link between the two lines is widely criticised. Five new luas lines are planned, the last of which will be opened in 2014, with the two existing lines set to be joined up by 2012.
There are plans to begin building work on the Dublin Metro (subway / underground) system set out in the Irish government's 2005 Transport 21 plan within the next few years. Although not confirmed, it is believed that the metro will be fully segregated from all traffic which will mean it will not disrupt traffic when in operation, unlike an on-street Luas Tram or the DART. The Metro North will bring rail access to areas and institutions currently lacking it, such as the Mater Hospital, Drumcondra (Croke Park, inter-city and suburban rail stop), Dublin City University, Ballymun, Swords and Dublin Airport. The Metro West will serve the large suburbs of Tallaght, Clondalkin and Blanchardstown.
Dublin is at the centre of Ireland's transport system. Dublin Port is the country's busiest sea port and Dublin Airport is the busiest airport on the island."