Quick turn round in vehicles (5)
I believe the answer is:
smart
'quick' is the definition.
(I've seen this before)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for smart that I've seen before include "Chic - hurt" , "Intelligent; clean, tidy" , "Trams (anag.)" , "Alick" , "Well-dressed" .)