Graphically determine the through$-$bandwidth for vehicles travelling from signalized intersection A towards signalized intersection D$.$ The intersections A$,$ B$,$ C$,$ and D are all on the same road and $1km$ away from the previous intersection $($i$.$e$.$ the distance from A to $B$ is $1km,$ from B to $C$ is $1km$ and from C to D is $1km).$ The operating speed on this road is $30kmph.$ The signal timing data is as follows:

$\backslash$table$[[\backslash$table$[[$Inter$-],[$section$]],\backslash$table$[[$Effective green$],[($s$)]],\backslash$table$[[$Effective red$],[($s$)]],\backslash$table$[[$Offset$],[($s$)]]],[$A$,40,40,0],[$B$,50,30,40],[$C$,40,40,0],[$D$,40,40,60]]$