Follow the movements of vehicle reversing kilometres (5)
I believe the answer is:
track
'follow the movements of' is the definition.
'vehicle reversing kilometres' is the wordplay.
'vehicle' becomes 'cart' (cart is a kind of vehicle).
'reversing' says the letters should be written in reverse.
'kilometres' becomes 'k'.
'cart' written backwards gives 'trac'.
'trac'+'k'='TRACK'
(Other definitions for track that I've seen before include "Footpath" , "Sign that one's passed" , "One song on CD?" , "A prepared course for racing on" , "Rough path or road" .)