Pit stop's a hazardous area
I believe the answer is:
minefield
'hazardous area' is the definition.
'mine field' can be an answer for 'area' (mine field is a kind of area). I am unsure of the 'hazardous' bit.
'pit stop's a' is the wordplay.
'pit' becomes 'mine' (mining pit).
'stop's a' becomes 'field' (I can't explain this - if you can you should give a lot more credence to this answer).
'mine'+'field'='MINEFIELD'
Can you help me to learn more?
(Other definitions for minefield that I've seen before include "Sensitive area" , "Dangerous area" , "Danger zone" , "Highly delicate situation (where one must watch one's step!)" .)