Parking on narrow road for flat surface (5)
I believe the answer is:
plane
'flat surface' is the definition.
(I've seen this before)
'parking on narrow road' is the wordplay.
'parking' becomes 'p' (abbreviation on road signs).
'on' says to put letters next to each other (in a down clue, letters appear on others).
'narrow road' becomes 'lane' (type of road).
'p'+'lane'='PLANE'
'for' is the link.
(Other definitions for plane that I've seen before include "Nepal (anag.)" , "Tool for smoothing wood" , "Woodworking tool" , "Flat surface; tree" , "barked?" .)