Cryptic puzzles on transport (7)

I believe the answer is:

rebuses

'cryptic puzzles' is the definition.
(a rebus is a visual puzzle)

'on transport' is the wordplay.
'on' becomes 're' ('on' can be mean 'with reference to').
'transport' becomes 'buses' (buses are public transport).
're'+'buses'='REBUSES'

(Another definition for rebuses that I've seen is " Word-picture puzzles".)

I've seen this clue in The Guardian.

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