Lack vehicle in small urban area (8)
I believe the answer is:
scarcity
'lack' is the definition.
(I've seen this before)
'vehicle in small urban area' is the wordplay.
'vehicle' becomes 'car' (car is a kind of vehicle).
'in' means one lot of letters goes inside another.
'small' becomes 's' (abbreviation - e.g. clothes size).
'urban area' becomes 'city' (city is a kind of urban area).
's'+'city'='scity'
'car' inserted within 'scity' is 'SCARCITY'.
(Other definitions for scarcity that I've seen before include "Something uncommon" , "Shortage" , "Shortness of supply" , "Inadequate supply" , "Want" .)