Last to use vehicle's a Welshman (5)
I believe the answer is:
evans
'a welshman' is the definition.
(common Welsh surname)
'last to use vehicle's' is the wordplay.
'last to' indicates one should take the final letters.
'vehicle's' becomes 'van's' (van is a kind of vehicle).
The last letter of 'use' is 'e'.
'e'+'vans'='EVANS'
(Other definitions for evans that I've seen before include "dame of acting fame" , "Theatrical dame" , "Lee --, British comedian" , "Dame Edith -, English actress" , "Female writer's real name" .)