Car being introduced earlier, not very unsafe? (10)
I believe the answer is:
precarious
'unsafe?' is the definition.
(similar in meaning)
I cannot understand how the rest of the clue works.
(Other definitions for precarious that I've seen before include "Not having a steady position" , "Hairy" , "Uncertain; likely to fall" , "having difficulty remaining upright" , "Highly insecure" .)