Queue of traffic (8)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
tailback
'queue of traffic' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for tailback that I've seen before include "Long queue of traffic" , "Lack a bit (anag.)" , "Queue of cars" , "delayed traffic" , "Traffic hold-up" .)