What do triangular warning signs mean in Northern Ireland?

Triangular signs in Northern Ireland are warning signs used to alert drivers to hazards ahead.

The red-bordered triangle warns rather than orders. The symbol inside identifies the hazard, such as bends, junctions, animals or changing road conditions.

For “What do triangular warning signs mean in Northern Ireland?”, the wider Northern Ireland context is this: Northern Ireland's Highway Code uses signs, signals and road markings together, so the safest reading is always the exact sign at the location plus any lane arrows, plates or temporary traffic management. Rules expressed as ‘must’ or ‘must not’ are legal requirements; advisory wording can still be used as evidence when responsibility for a collision is considered.

For this exact question — “What do triangular warning signs mean in Northern Ireland?” — the practical point is: Reduce speed early enough to react to the hazard and look for supplementary plates giving distance or extra detail. The answer should be applied to the actual signs, conditions, licence wording or parking rules in force at the time, because temporary restrictions and individual DVA decisions can change the ordinary position.

This Northern Ireland-specific page on “What do triangular warning signs mean in Northern Ireland?” was checked against the attached official sources before publication, with nidirect/DVA and the Northern Ireland Highway Code used ahead of generic UK motoring articles. If the rule, road layout or personal licence condition changes, those primary sources are the ones to re-check.