City could be set on model that's most up to date (6)
I believe the answer is:
latest
'most up to date' is the definition.
(I've seen this before)
'city could be set on model' is the wordplay.
'city' becomes 'la' (Los Angeles).
'could be' indicates an anagram.
'on' is a charade indicator (letters next to each other).
'model' becomes 't' (Ford Model T car).
'set' is an anagram of 'est'.
'est' put after 't' is 'test'.
'la'+'test'='LATEST'
'that's' is the link.
(Other definitions for latest that I've seen before include "Most recent (news)" , "Most recent, hot off the press" , "Most recent or tardiest" , "Brand new, just out" , "Most up to the minute" .)