Speed limits in Ireland: know the laws for your next road trip

Here, we take you through speed limits on different roads, speed limits at different times of day and what to expect if you’re caught speeding.

First things first: Irish speed limits are given in kilometres per hour (kph) so if you’re used to measuring your speed in miles per hour (mph), you’ll need to convert numbers on road signs into something more meaningful.Your speedometer should have both numbers marked, usually in another colour and on the inside of the semicircle.

Thankfully, there shouldn’t be any confusion about what a speed limit sign looks like, as most of them are almost identical to road signs in the UK. 

Another useful point to remember is that speed camera detectors are illegal. You should turn off any camera detection features on mobile apps and leave speed detection devices at home to avoid any punishments from the Garda (Irish police force).¹

There are also different speed limits for different types of vehicles. The 80 kph (49 mph) limit for any vehicle towing a trailer or caravan is probably the most relevant for drivers visiting from the UK.

If you’re towing a trailer or caravan through Ireland, you should never exceed the 80 kph (49 mph) limit even when travelling on motorways and national roads.

Special speed limits may also apply:

• at different times of day
• on different sides of a dual carriageway
• on particular sections of road, for example, in a tunnel where a lane must be closed 
• where there are a series of bends
• at roadworks

You should never exceed 120 kph (74 mph) when travelling on Irish motorways and remember, if you’re towing a trailer or caravan this limit is reduced to 80 kph (49mph).

There may be times when you’re asked to drive at slower speeds, especially when approaching and driving through roadworks. Be careful and look out for roadside signs and information on gantries for any changes in speed limits that you’ll need to stick to.

The Road Safety Authority (RSA) recommend that you abide by the two-second rule to ensure you keep a safe stopping distance from vehicles in front of you.

This means keeping two seconds away from vehicles in front in good driving conditions and doubling the distance when the road surface is wet. You can even try saying ‘Only a fool breaks the two-second rule’ twice in your head as the car in front of you passes a fixed point, like a sign. If you pass the same fixed point before you’ve finished saying it, you’re too close. 

For more extreme weather conditions, it's advised to repeat the saying four or five times instead.

• RAC Temporary Car Insurance
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• RAC Route Planner

Variable speed limits, similar to those used on our smart motorways, are due to hit roads in Ireland. Dublin’s M50 has been earmarked for an €80 million overhaul to install gantry signs that close lanes and reduce speeds in the event of a crash or severe weather.²

There are no plans to open up the hard shoulder for use as another driving lane.

National speed limits work slightly differently in Ireland. There’s a difference between speed limits on national roads and the speed indicated by the ‘national speed limit’ road sign:

• speed limit on national roads: 100 kph (62 mph)
• national speed limit: 80 kph (49mph) 

The ‘national speed limit’ sign is almost identical to the one in the UK except that it uses a series of diagonal stripes on a white circle rather than the single black stripe that we’re used to.

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Slower speed limits may be set by local authorities on roads in densely populated areas or outside schools. Keep an eye out for signs.

Although most speed limits in Ireland apply 24 hours a day, some local authorities may enforce limits between certain time periods and different days of the week. For example, you might find that a 30kph (18mph) limit applies Monday to Friday close to some schools.

The periodic speed limits are displayed in one of two ways:

• a standard road sign with an information plate giving details of when the temporary rules apply.
• an electronic sign which only lights up when the periodic limit applies. This may also feature two flashing amber lights.

If you’re caught speeding in Ireland, you’ll face an €80 fine and three points on your licence. You’ll have 28 days to pay the fine before it increases to €120 and a possible five points on your licence. If you fail to pay the fine after another 28 days and you’re convicted for speeding in court, you could face a maximum fine of €1,000.

Back in 2019, plans for graduated penalties were approved by the Irish Cabinet before being scrapped in 2021.³