Reportedly cycled towards mass police barrier (9)
I believe the answer is:
roadblock
'police barrier' is the definition.
(barrier the police might set up)
'reportedly cycled towards mass' is the wordplay.
'reportedly' shows a homophone (sound like).
'cycled' becomes 'rode' (ride can mean to ride a bike).
'towards' means one lot of letters go next to another (I've seen this in other clues).
'mass' becomes 'block' (mass can mean a lump or block of a substance).
'rode' sounds like 'road'.
'road'+'block'='ROADBLOCK'
(Other definitions for roadblock that I've seen before include "Traffic-halting barrier" , "Checkpoint" , "Paving stone" , "Police barricade to halt traffic" , "Barrier to traffic" .)