Who has priority when two lanes merge into one in Northern Ireland?

Neither driver should force priority when two lanes merge; follow signs and markings and merge safely into the available gap.

Where traffic is slow and lanes are directed to merge, the Highway Code concept of merge in turn can help use road space efficiently. At higher speeds, plan the merge earlier.

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 — “Who has priority when two lanes merge into one in Northern Ireland?” — the practical point is: Match speed, signal where useful and avoid accelerating to block another vehicle from joining. 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.