Driving aids (4)
I believe the answer is:
tees
'driving aids' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for tees that I've seen before include "Golfer's equipment" , "Middlesbrough's river" , "Sides of Trent" , "Golfer's supports; river" , "Northern river" .)