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A circular sign with a red border showing the number 100.100
regulatory

Maximum speed limit 100 km/h

The maximum speed on this road is 100 km/h.

What it means in practice

100 km/h is the default limit on national roads, both primary and secondary, which carry green signs with N route numbers. It applies to dual carriageways that are not motorways.

Description

A circular sign with a red border showing the number 100.

speednational road

Sources

  • Rules of the Road · Road Safety Authority · Edition reflecting road traffic law as at 1 March 2025
    Last checked 2026-09-08

Questions that use this sign

  • You are driving a car towing a caravan. Which of these signs sets the maximum speed you may travel at, whatever the road?

    Road signs · hard

Practise sign questions

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Independent learning application. Not affiliated with the Road Safety Authority or the official Driver Theory Test service. TheoryLane questions are written by TheoryLane from published Irish road-rule sources.