Quick turn round in public transport (5)
I believe the answer is:
smart
'quick' is the definition.
(I've seen this before)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for smart that I've seen before include "Clean, tidy; sting" , "well-kept" , "Well turned out" , "Spruce; sting" , "Sort of card" .)