Lines of waiting people or vehicles (6)
I believe the answer is:
queues
'lines of waiting people or vehicles' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for queues that I've seen before include "lots of waiters" , "Lines of waiters" , "Waits in line" , "Line of waiting people or vehicles" , "Lines of waiting people or vehicles" .)