Crossword Genius

They call for patient driving (10)

Ross

I believe the answer is:

ambulances

I'm a little stuck... Click here to teach me more about this clue!

'they' is the definition.
Both the definition and answer are plural nouns.
Perhaps they are linked in a way I don't understand?

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for ambulances that I've seen before include "Emergency vehicles" , "plurality of emergency resources" .)

I've seen this clue in The Globe and Mail.
Want a hint initially instead of a full solution? Install my app