Columns of vehicles are grouped in {TAIL ~ travel zones} alternating with empty zones , and are laid out in a centrally controlled grid pattern of {HEAD ~ fastroads}  
Columns of vehicles are grouped in { TAIL ~ travel zones } alternating with empty zones , and are laid out in a centrally controlled grid pattern of { HEAD ~ fastroads }
OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH