Roads in Ireland

The island of Ireland, comprising Northern Ireland and the Republic of Ireland, has an extensive network of tens of thousands of kilometres of public roads, usually surfaced. These roads have been developed and modernised over centuries, from trackways suitable only for walkers and horses, to surfaced roads including modern motorways. Driving is on the left-hand side of the road. The major routes were established before Irish independence and consequently take little cognisance of the border other than a change of identification number and street furniture. Northern Ireland has had motorways since 1962, and has a well-developed network of primary, secondary and local routes. The Republic started work on its motorway network in the early 1980s; and historically, the road network there was once somewhat less well developed. However, the Celtic Tiger economic boom and an influx of European Union structural funding, saw national roads and regional roads in the Republic come up to international standard quite quickly. In the mid-1990s, for example, the Republic went from having only a few short sections of motorway to a network of motorways, dual carriageways and other improvements on most major routes as part of a National Development Plan. Road construction in Northern Ireland now tends to proceed at a slower pace than in the Republic, although a number of important bypasses and upgrades to dual carriageway have recently been completed or are about to begin.

Roads in Northern Ireland are classified as either Highways, motorways (shown by the letter M followed by a route number, e.g. M1), A-roads (shown by the letter A followed by a route number, e.g. A6), B-roads (shown by the letter B followed by a route number, e.g. B135) and other roads. There are two types of A-roads: primary and non-primary.

Roads in the Republic are classified as motorways (shown by the letter M followed by a route number, e.g. M7), national roads (shown by the letter N followed by a route number, e.g. N25), regional roads (shown by the letter R followed by a route number, e.g. R611) and local roads (shown by the letter L followed by a route number, e.g. L4202). There are two types of national roads: national primary routes and national secondary routes.

Road signs in Northern Ireland follow the same design rules as the rest of the United Kingdom. Distance signposts in Northern Ireland show distances in miles, while all signposts placed in the Republic since the 1990s use kilometres. The Republic's road signs are generally bilingual, using both official languages, Irish and English. However, signs in the Gaeltacht (Irish speaking areas) use only Irish. The Irish language names are written in italic script, the English in capitals. Signs in Northern Ireland are in English only. Warning signs in the Republic have a yellow background and are diamond-shaped, those in Northern Ireland are triangle-shaped and have a white background with a red border.

Speed limits in Northern Ireland are specified in miles per hour. Those in the Republic use kilometres per hour (km/h), a change introduced on 20 January 2005.^[1] This involved the provision of 58,000 new metric speed limit signs, replacing and supplementing 35,000 imperial signs.