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