The traveller again needs parking (3)
I believe the answer is:
rep
'the traveller' is the definition.
(travel company worker)
'again needs parking' is the wordplay.
'again' becomes 're' (prefix meaning 'again').
'needs' says to put letters next to each other.
'parking' becomes 'p' (abbreviation on road signs).
're'+'p'='REP'
(Other definitions for rep that I've seen before include "Repertory theatre" , "agent" , "Fabric with a ribbed surface" , "Theatre; fabric; salesman" , "Salesperson" .)