Northern Ireland is quite small, really. It's about 100 miles wide at its very widest point, measured from Bangor on the east coast to the village of Belleek, where the creamy interwoven pottery comes from, deep in the heart of Fermanagh's lake land. From its most northerly tip at Torr Head, battered by the Atlantic breakers, south to the very wiggly border with the Republic of Ireland is a distance of about 75 miles.

This patch of the UK is home to about 1.5 million inhabitants, the vast majority of whom live in and around Belfast. So the need for a motorway network was never terribly acute. Ambitious early plans for a substantial and sophisticated network with fingers connecting all parts of the province did not materialise. For the most part, this was due to financial priorities during the 1960s and 1970s being focused elsewhere, as the continuing 'Troubles' ate up resources.

But fear not motorway fans, for a compact and bijou little network does indeed exist, and it brings joy and frustration to its users day and daily. The numbering is all of its own, and should not be confused with any motorways of the same nomenclature in the rest of Ireland, or in Great Britain.

The M1

The M1, perhaps counter-intuitively, does not link Belfast with the only capital city reachable by land, Dublin. The longest of Northern Ireland's motorways, it heads west from Belfast but Dublin-bound traffic has to leave it eight miles out at the Sprucefield junction¹ and join the A1 heading south. This has caught out a number of unsuspecting tourists.

The M1 continues for another 40 miles west, visiting four of Northern Ireland's six counties and crossing the River Lagan several times, before it reaches Dungannon. Here it peters out and becomes the A4, which is a notorious accident black spot: drivers forget to change their driving style from 'motorway' setting to 'country road'.

Although there are no service stations on any of Northern Ireland's motorways, there is something akin to one just after the end of the M1. The Killymaddy Amenities area has tourist information, a craft centre, a cafe and a play area.

Drivers coming into Belfast on the M1 are warned that the hard shoulder becomes a bus lane shortly after the Sprucefield junction.

The M12

This is a tiny spur which leads off the M1, connecting it to the new town conurbation of Craigavon.

The M2

The M2 leaves Belfast up a steep hill past Belfast Castle and the zoo, and strikes out heading vaguely northwards. With the exception of a small section of the M90 in Scotland, its one-in-15 gradient makes it the steepest motorway in the UK, necessitating a crawler lane on the uphill side. From the top of this hill, the traveller has a fabulous view over Belfast Lough², with planes landing at the George Best Belfast City Airport on the far side: a panorama which is nothing short of breathtaking.

For those leaving Belfast, the M2 is the route which takes you part of the way to the other Belfast airport, the International. At the top of the hill is a massive roundabout with six exits. Its proper name is the Sandyknowes roundabout, but locals call it the Snotty-nose. This junction connects travellers with the A8(M), of which more later.

The M2 continues in a north-westerly direction, skirting the top of Lough Neagh (which can just be glimpsed from the motorway), before it ends at Randalstown, becoming the A6. As this is the main route between Belfast and Londonderry, it tends to be used heavily by lorries. The 22 miles of the M2 lie entirely within County Antrim, and it is the busiest road in the province.

There is one other tiny bit of the M2 which forms a little semi-circle around Ballymena. This dates back to the early plans for motorway connections in all directions, when construction was carried out in the order of greatest urgency, rather than sequentially out from Belfast. There is now no intention to construct a full motorway grade connection between this bit of the M2 and the main section. However, a high-grade dual carriageway now joins them, so the experience for drivers is pretty similar.

The A8(M)

At 0.9 miles (1.5km) long, this is one of the world's shortest stretches of motorway, and a contender for the 'World's Most Pointless Motorway'. You'd take this if you were heading to the major ferry port of Larne.

The M3

This is a very fancy name for what is in essence a bridge over the River Lagan; sometimes called the Lagan Bridge, or the Cross Harbour Link. The construction of this graceful, curving bridge, less than a mile long, was an ambitious project, as most of it is on elevated pillars. Unsurprisingly, it is – cost-per-mile – the most expensive motorway in Northern Ireland.

However, its construction (together with that of its sibling railway bridge) greatly eased city centre congestion by transporting traffic heading east towards Bangor straight onto the Sydenham bypass, the oldest dual carriageway in Northern Ireland. Arguably more importantly, it links the various railway stations in the city, making it easier for train users to get about on a seamless network.

It is recognised as one of the most successful local road-building projects and, at 0.8 miles (1.3km) long, is Northern Ireland's shortest motorway.

The M5

Running beside the M2 as it leaves Belfast, the M5 makes its short journey of just under two miles along the northern side of Belfast Lough, until it reaches Whiteabbey. Its signposts contain brown tourist pointers for visitors wishing to take the scenic route (the A2) all around the coast of Northern Ireland. The two lanes of the M5, immediately adjacent to the two of the M2, with a fifth lane in each direction exiting to the docks, amount to fully ten lanes across in some places.

This was at one time the widest patch of motorway in the UK. It was constructed on reclaimed land, and lies only a few feet above sea level.

Despite plenty of signs showing which is the M5 and which the M2, someone always seems to be caught out at the last minute, desperately trying to cross four lanes of traffic to get onto their desired motorway.

The Westlink

Not strictly a motorway – it's the A12 – the Westlink connects the M1 and M2 and acts as Belfast's bypass (although it's more of a 'through-put'). It was an extremely difficult project to engineer, involving cuttings and retaining walls through a busy urban setting. .

The Westlink rapidly became the most hated road in Belfast. At times, users ran the additional risk of local youths dropping stones and boulders onto the carriageway from the footbridges which cross it, although most of these have now been caged in.

Substantial upgrades in 2007 and 2008 removed the major roundabouts on this one-mile stretch of tarmac hell, and replaced them all with underpass intersections. Theoretically, drivers shouldn't need to stop unless they are leaving the Westlink. In practice, rush hour traffic can still be extremely slow-moving.

The underpass at what was the Broadway roundabout, at the foot of the Falls Road and beside the Royal Victoria Hospital, became a newsworthy sight during the heavy rains and subsequent flooding of September 2008. Water could not drain away quickly enough, turning the underpass into a swimming pool. A modern sculpture has been unveiled which will eventually stand on the site of the former roundabout, symbolising a positive outlook for the future.

Tips for Users

The vast majority of the network has two lanes in each direction, with a hard shoulder on the left for emergency use only, and a metal central barrier. Drivers should stay in the left lane unless they are overtaking. The speed limit is not explicitly stated, but is the national speed limit of 70mph unless otherwise indicated. (The whole of the M3 has a speed limit of 50mph due to its curve and lack of hard shoulder).

Lane discipline is reasonably well practised. Where two lanes merge or traffic is joining from a slip road at busy times, a 'zipper' approach, or merging in turn, is common, but should not be automatically expected. The car letting you in may flash its lights to let you know you can proceed. It is considered polite for the car which has been allowed in to indicate thanks with either a wave of the driver's hand or quick flash of the hazard-warning lights. This is not endorsed by the Highway Code, but it is a common sight.

Locals rarely use junction numbers when talking about exits. Junction six on the M1 will be referred to as 'The Saintfield Road exit', for example. This can be frustrating for visitors either obtaining directions or listening to local traffic bulletins. It is not that informative to learn that 'there are the usual build-ups in the usual locations', nor that 'there's been an accident just past the Ballybogey Bridge'. Lights being flashed by oncoming traffic can be a warning that there's either an accident or some other incident ahead, or that there is a speed cop about. Speed cameras are a rarity.

Learner drivers display the letter L and are not permitted on motorways. But in Northern Ireland those who pass their driving test display the letter R on their vehicle, are restricted to 45mph for one year, and are permitted to drive on motorways.

Happy motoring!