Vehicles to drive with patience, it's said (10)
I believe the answer is:
ambulances
'vehicles' is the definition.
(ambulance is a kind of vehicle)
'drive with patience it's said' is the wordplay.
I cannot really understand how this works, but
'it's' could be 'es' ('e' can mean 'electronic' which is similar to 'IT') and 'es' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
'to' acts as a link.
Can you help me to learn more?
(Other definitions for ambulances that I've seen before include "Emergency vehicles" , "plurality of emergency resources" .)