Speed Limit 100 km

Speed Limit 100 km signs appear on dual carriageways throughout Ireland including the N1 dual sections north of Dublin, N2 dual carriageway sections in Meath and Monaghan, N4 dual sections in Westmeath and Roscommon, N7 dual carriageway between Dublin and Kildare, N8 dual sections between Cork and Dublin, N11 dual carriageway in Wicklow, N18 dual sections in Clare, and N25 dual carriageway in Waterford.

The 100 km/h limit applies to divided carriageways with central reservations but not motorways (which have 120 km/h limits).

The maximum speed is 100 km/h for cars and motorcycles on this dual carriageway.

Learner drivers must not exceed 80 km/h even on 100 km/h roads.

Heavy goods vehicles and buses have maximum speeds of 90 km/h regardless of posted limits.

The limit applies to high-standard dual carriageways with central reservations and grade-separated junctions.

Drivers must reduce speed for weather conditions, traffic, or visibility constraints. 100 km/h is the second-highest speed limit in Ireland after 120 km/h on motorways.

Exceeding 100 km/h limits results in graduated penalties: 101-110 km/h (€80, 2 points), 111-120 km/h (€80, 4 points), 121+ km/h (€200, 5 points, court proceedings).

GoSafe camera enforcement operates extensively on dual carriageways.

Excessive speeds often result in dangerous driving charges: fines to €5,000, 5 penalty points, potential imprisonment, and disqualification.

Novice drivers exceeding 80 km/h on 100 km/h roads face special penalties as they're violating novice driver restrictions.

Commercial vehicles exceeding 90 km/h face additional operator license consequences.

Speed limit knowledge including 100 km/h dual carriageway limits features extensively in theory tests.

Questions test understanding that different driver and vehicle categories have different maximum speeds: full license holders 100 km/h, learner drivers 80 km/h, commercial vehicles typically 90 km/h.

You must recognize dual carriageways by central reservations and understand that 100 km/h applies only to divided roads, not single carriageways.

Practical tests on dual carriageways assess appropriate speed selection: examiners expect adherence to 100 km/h limits where appropriate for conditions, understanding of graduated speed restrictions, and recognition that speeds must be adjusted for weather and traffic.