When there's jam, pull over second expensive car by wheel (8)
I believe the answer is:
tomorrow
'when there's jam' is the definition.
I can't judge whether this defines the answer.
'pull over second expensive car by wheel' is the wordplay.
'pull' becomes 'tow' (to tow is to pull or drag).
'over' is an insertion indicator.
'second' becomes 'mo' (both are short periods of time).
'expensive car' becomes 'rr' (short for Rolls Royce).
'by wheel' becomes 'o' (O looks like a wheel. I am not sure about the 'by' bit.).
'mo'+'rr'+'o'='morro'
'tow' going around 'morro' is 'TOMORROW'.
Can you help me to learn more?
(Other definitions for tomorrow that I've seen before include "In the near future" , "Time that's coming" , "The next day" , "The day that never comes" , "It's manana in Spain" .)