Cut into vehicle — someone trapped may be this? (8)
I believe the answer is:
shackled
'someone trapped may be this?' is the definition.
(someone caught may be shackled)
'cut into vehicle' is the wordplay.
'cut' becomes 'hack' (hacking is a kind of cutting).
'into' means one lot of letters goes inside another.
'vehicle' becomes 'sled' (sled is a kind of vehicle).
'hack' put within 'sled' is 'SHACKLED'.
(Other definitions for shackled that I've seen before include "Confined, as with fetters" , "In chains" , "Restrained" .)