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