Given, Peak hour factor =PHF=0.78125 Maximum service flow rate of LOS =MSF=1280 FHV=1 Road under familiarity adjustment ejector =fp=1 Now, we know that, number of lane (N) {N}=\;{ {DDHV}}/{ {PHF} × {MSF} × {F}_{ {HV}} × {f}_{ {p}}} Here, DDHV = Directional distribution hour volume. DDHV =122270×0.6=7362 ∴N=
7362
0.78125×1280×1×1
=7.362=8 lanes Number of extra lanes =8−2=6 lanes.