
Like I use 2-4-2-4-2-... bus design (like this: ..vvvv..vvvv..vvvv.. ), as many of us do. Because it's so convenient to use underground belts under 4-belt-bus.
And then I have to use underground pipe only 6-tile long ( .\vvvv/\vvvv/), because otherwise it comes out on the last belt of the (2)-(4)-(2)-(3+1) ( .\vvvv..vvv/.. )