What do red circular road signs mean in Northern Ireland?

Red circular signs generally give prohibitions or restrictions; the exact symbol or wording tells you what is forbidden.

Examples include speed limits, no-entry and vehicle restrictions. A red ring is a strong visual cue that the sign is regulating what traffic may do, but you still need to read the symbol inside it.

For “What do red circular road 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 red circular road signs mean in Northern Ireland?” — the practical point is: Treat the restriction as applying from the sign until it is ended, replaced or varied by later signing, and do not rely on sat-nav instructions where they conflict with a traffic sign. 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 red circular road 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.