so that {HEAD ~ particulate material} placed in the hopper truck may be spread in {TAIL ~ a uniform layer} on a road surface over a predetermined path width 
spread in
so that { HEAD ~ particulate material } placed in the hopper truck may be spread in { TAIL ~ a uniform layer } on a road surface over a predetermined path width
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH