Drivers start to turn in space when reversing vehicle (8)

'vehicle' is the definition.
(motorcar is a kind of vehicle)

'drivers start to turn in space when reversing' is the wordplay.
'drivers' becomes 'rac' (I've seen this in other clues).
'start to' indicates taking the first letters.
'in' means one lot of letters goes inside another.
'space' becomes 'room' (room is a kind of space).
'when reversing' says the letters should be written in reverse.
The first letter of 'turn' is 't'.
't' inserted into 'room' is 'rotom'.
'rac'+'rotom'='racrotom'
'racrotom' written backwards gives 'MOTORCAR'.