Vehicle: auto oddly turning over on side (4)
I believe the answer is:
taxi
'vehicle' is the definition.
(taxi is a kind of vehicle)
'auto oddly turning over on side' is the wordplay.
'oddly' means one should take alternating letters.
'turning over' says the letters should be written backwards.
'on' says to put letters next to each other.
'side' becomes 'xi' (**).
The alternating letters of 'auto' are 'at'.
'at' in reverse letter order is 'ta'.
'ta'+'xi'='TAXI'
(Other definitions for taxi that I've seen before include "Motor-cab" , "Prepare to fly" , "move slowly along the ground" , "type of vehicle" , "Move along a runway" .)