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