Legislation on parking agreements (5)
I believe the answer is:
pacts
'agreements' is the definition.
(pact is a kind of agreement)
'legislation on parking' is the wordplay.
'legislation' becomes 'acts' (I've seen this before).
'on' says to put letters next to each other.
'parking' becomes 'p'.
'acts' put after 'p' is 'PACTS'.
(Other definitions for pacts that I've seen before include "Accords, treaties" , "Agreements" .)