The parking card shows the rate (4)
I believe the answer is:
pace
'the rate' is the definition.
(pace is a kind of rate)
'the parking card' is the wordplay.
'the parking' becomes 'p'.
'card' becomes 'ace' (I've seen this before).
'p'+'ace'='PACE'
'shows' acts as a link.
(Other definitions for pace that I've seen before include "speed of movement" , "Clip" , "With due respect" , "Speed of a single step?" , "Rate of progress" .)