On the road, cautionary advice to pedestrians who appear abandoned (4,4)

I believe the answer is:

look left

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'on the road cautionary advice to pedestrians' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.

'appear abandoned' is the wordplay.
'appear' becomes 'look' (synonyms).
'abandoned' becomes 'left' (I've seen this before).
'look'+'left'='LOOK LEFT'

'who' acts as a link.

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