Road signs, Route for trams only
What does a blue circle with a tram mean?
A route reserved for trams only.

A blue circle with a white tram.
What you must do
Do not drive here unless you are permitted; the route is for trams.
Where you will see it
In city centres with a tram network.
Test yourself
The theory test asks you to recognise signs like this one. Try the road and traffic signs short test (with an easy and a hard set), or read the signs revision notes. Source: Know Your Traffic Signs.
Other common road signs
Meaning based on Know Your Traffic Signs and The Highway Code. The sign image is an official Department for Transport sign (Crown copyright) from Wikimedia Commons, reused under the Open Government Licence or the public domain. Always check the current Highway Code on gov.uk. Not affiliated with or endorsed by the DVSA.