In order to maintain alternating {TAIL ~ nonstop traffic flow} on {HEAD ~ the nonstop lane}, three moving zones are marked along the fastroads by signal emitting fixtures operated according to signal progression principles 
In order to maintain alternating { TAIL ~ nonstop traffic flow } on { HEAD ~ the nonstop lane } , three moving zones are marked along the fastroads by signal emitting fixtures operated according to signal progression principles
OTH OTH OTH OTH OTH TAIL 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 OTH OTH OTH OTH OTH OTH OTH OTH