Do they enable round trips? (4,5)

I believe the answer is:

ring roads

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'do they enable' is the definition.
I know nothing about this answer so I cannot tell whether this works.

'round trips?' is the wordplay.
'round' becomes 'ring' (synonyms).
'trips?' becomes 'roads' (I can't explain this - if you can you should believe this answer much more).
'ring'+'roads'='RING-ROADS'

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I've seen this clue in The Daily Express.

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