When does the vehicle in the photograph have priority?

Correct answer

Only when travelling on emergency duty and indicating it correctly.

It has priority while on emergency duty and correctly signalling its presence. Normally it uses special lights and an audible emergency signal together; it must use lights alone when omitting the audible signal creates no danger to others. A fire engine does not have priority on every journey. Other users must facilitate safe passage as circumstances require, normally moving right or stopping if necessary; the emergency corridor rules apply where relevant on congested motorways or dual carriageways.