ISD is designed for the longest time in this case left
6 lanes faciliuty is 3 add lanes = for each additional two lanes is 0.7 x 2= 1.4 footnote page 660
and 16 ' lane( page 661 last paragraph ) = 16/12=1.33 x 0.7 /2 = 0.455 time to cross the median
Total tg= 11.5 + 0.455 + 1.4 =13.355...
