Merging traffic sign: meaning and rules

What does the merging traffic sign mean?

It is a warning triangle. Know your traffic signs lists “traffic merges from the left” and a version where traffic merges onto the main carriageway. The broad line is your road.

Quick quiz

What does the sign at the top of this page mean?

Traffic joins from the left ahead.
A side road joins from one side ahead.
The dual carriageway ends ahead.

Show answer

A. Traffic joins from the left ahead. Traffic merges from the left ahead (Know your traffic signs). Source: Know your traffic signs: warning signs, GOV.UK; The Highway Code, rule 134, GOV.UK; Traffic sign images, Department for Transport, GOV.UK

Where will you see it?

Where a slip road or another lane joins a main road or dual carriageway.

What should you do?

Look ahead and in your mirrors for vehicles joining. If it is safe, adjust your speed or move to another lane to give them room. In very slow traffic, merging in turn is recommended (rule 134).

What do people get wrong?

Speeding up to stop a joining driver getting in. Give them room if you can do so safely.

Common questions

Who has priority when traffic merges?

Traffic joining the main road normally gives way, but drivers on the main road should help it join where they can safely do so.

What does merging in turn mean?

In very slow traffic, vehicles from each lane take turns to move into the remaining lane. The Highway Code recommends it only at very low speed (rule 134).

Compare with

Want to test someone else? Play a road-sign quiz with friends and family.

Sources

Checked on 3 November 2026 against Know your traffic signs (warning signs) and The Highway Code rule 134.

Contains public sector information licensed under the Open Government Licence v3.0. Traffic sign images are Crown copyright, from the Department for Transport. Sources and image credits.