One lane for each item will be more than enough for any main bus.
Make your Main Bus with much less space. You can make faster belts with 2x / 4x / 8x / 16x / 32x / 64x / 128x / 256x the Express Belt. Work in Progress. Missing some graphics.
Mods introducing new content into the game.
One lane for each item will be more than enough for any main bus.