Rocks and ice bounced around truck up front (2,7)
I believe the answer is:
in advance
'front' is the definition.
(similar in meaning)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for in advance that I've seen before include "Before the event" , "Beforehand - can invade accordingly (2.7)" , "Ahead in place or time" , "early" .)