Buffer of a driver with a broken rib and a gashed head (3,3)
I believe the answer is:
air bag
'buffer of a driver' is the definition.
The definition suggests a singular noun which matches the answer.
'a broken rib and a gashed head' is the wordplay.
'broken' indicates an anagram.
'head' indicates taking the first letters.
The initial letters of 'and gashed' is 'ag'.
'rib' anagrammed gives 'irb'.
'a'+'irb'+'ag'='AIR BAG'
'with' acts as a link.
Can you help me to learn more?
(Other definitions for air bag that I've seen before include "A safety feature in a car" , "Car safety cushion" , "Balloon or protective device in car" , "Rapidly-inflating car safety device" , "A safety restraint in a car" .)