High-quality dual carriageway

A High-quality dual carriageway (HQDC) is a category of road in the Republic of Ireland. It is an all-purpose dual carriageway road type built to near motorway standards, but without motorway classification or motorway restrictions. High-quality dual carriageways have full grade-separated access and do not have junctions with minor roads. Such roads in the Republic of Ireland have been built as part of the 2000-2006 and 2007 to 2013 National Development Plans, including interurban routes from Dublin to other cities.

While HQDCs or roads of similar type exist in a number of countries (a British example being the A55 road in Wales), this article concentrates mainly on such roads in the Republic of Ireland.

Specifications

Standard motorways: 52,000 vehicles AADT - annual average daily traffic. The road type is all-purpose dual carriageway (D2AP), but with the same specifications as motorway: a carriageway width of 7 metres (23 ft) and a hard shoulder of 2.5 metres (8 ft 2 in) width. HQDCs are limited access (grade-separated junctions only) and not intended to have junctions with minor roads. Junctions with major roads are grade-separated and to motorway standards.

All HQDCs in Ireland currently form part of national primary roads, and therefore use the national road speed limit of 100 km/h (62 mph). There are exceptions however, as special speed limits may now be specified for sections of road if the local authority passes a by-law....
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