{HEAD ~ a communication device} arranged in the second vehicle and which communicates {TAIL ~ the position} of the second vehicle as determined by said second positioning system to the first vehicle 
communicates
{ HEAD ~ a communication device } arranged in the second vehicle and which communicates { TAIL ~ the position } of the second vehicle as determined by said second positioning system to the first vehicle
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH