Apparatus and method for defining {TAIL ~ a safety zone} using a radiation source for {HEAD ~ a vehicle} 
Apparatus and method for defining { TAIL ~ a safety zone } using a radiation source for { HEAD ~ a vehicle }
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD