Who assesses some road plant? (6)

'plant?' is the definition.
The answer and definition can be both people as well as being singular nouns.
Maybe there's a link between them I don't understand?

'who assesses some road' is the wordplay.
I cannot quite understand how this works, but
'some' could be 'a' and 'a' is found within the answer.
'road' could be 'rd' (abbreviation) and 'rd' is located in the remaining letters.
The remaining letters 'ger' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?