Driver's compartment (3)
I believe the answer is:
cab
'driver's compartment' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for cab that I've seen before include "It has the authority to confiscate the proceeds of crime, in short" , "Taxi to hold an engine-driver" , "info for citizens provided here" , "vehicle" , "Hired car" .)