New driver on road runs over plainsman (7)
I believe the answer is:
llanero
'plainsman' is the definition.
(I've seen this before)
'new driver on road runs over' is the wordplay.
'new driver' becomes 'l'.
'on' says to put letters next to each other.
'road' becomes 'lane' (I have seen 'Small road' mean 'lane' so perhaps 'road' could also mean 'lane').
'runs over' becomes 'ro' (this might be a standard abbreviation which I don't know about).
'l'+'lane'+'ro'='LLANERO'
(Other definitions for llanero that I've seen before include "Liver on plain" , "Plainsman" , "Plain-dweller" , "Plain person" , "Plains dweller" .)