Where citizens can get advice on transport (3)

I believe the answer is:

cab

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'transport' is the definition.
(I know that cab is a type of carriage)

I don't understand the remainder of the clue.

(Other definitions for cab that I've seen before include "'The authority collects money made from crime, initially (3)'" , "Transport" , "Hired car" , "Driver's compartment, in lorry say" , "A taxi in America" .)

I've seen this clue in the Evening Standard.

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