Begin with 'driver' and 'operator'.
You will find both those dictionaries most valuable.
When 'booking' a motorist, the Police most often state: "...driving a vehicle...', which would be incorrect if the motorist was not receiving any reward, whether for payment or payment in kind.
Printed copy · Anthology Volume 1, page 872Printed copy from The Tender For Law Anthology, Volume 1, page 872 (printed 14 June 2014). Added by this site; not part of the Facebook export.