Road works have one new rule (6)
I believe the answer is:
ordain
'rule' is the definition.
(I've seen this before)
'road works have one new' is the wordplay.
'works' indicates an anagram.
'have' says to put letters next to each other.
'one new' becomes 'in' (I've seen this in other clues).
'road' with letters rearranged gives 'orda'.
'orda'+'in'='ORDAIN'
(Other definitions for ordain that I've seen before include "Initiate as priest" , "Officially order" , "Destine" , "Decree or consecrate" , "Appoint - admit to holy orders" .)