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High Quality Dual Carriageway

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High Quality Dual Carriageway
N1 through Ravensdale - Coppermine - 14599.jpg
The N1 is a HQDC
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A High Quality Dual Carriageway (HQDC) is a road type in Ireland, although the term is also unofficially applied to similar roads in the United Kingdom.

Irish usage

To fall under this category, a road must (as the name suggests) be an all-purpose road built as a dual carriageway with the vast majority of its junctions being grade-separated, and equipped with hard shoulders. All are part of the National Primary Road network and subject to the standard 100 km/h speed limit, though this may be varied locally. As they are not motorways, all classes of traffic (including cyclists and farm traffic) are allowed onto them.

A large number of HQDCs were upgraded to motorways in 2009, including sections of the N2, N3, N18, and N20.

United Kingdom usage

In the United Kingdom, the term is unofficially used to refer to any road that to the layperson appears to be a "motorway" (and is often colloqually referred to as such), but that has green signage. Such roads may or may not possess hard shoulders. They are usually parts of long-distance routes; examples include the A2 in Kent between the M25 and M2, the A14, and the A42.

The term is occasionally also used to refer to more local sections of routes with grade-separated junctions, such as the A454 Black Country Route between Wolverhampton and Walsall, the A13 past Dagenham, and the A4053 Coventry Inner Ring Road.

The term is also sometimes confused with non-motorway Special Roads.



High Quality Dual Carriageway
Road Basics
Physical layoutSingle track • Single carriageway • Dual carriageway • High Quality Dual Carriageway • Road Widths • Urban Streets
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