Make underground belts work like underground pipes.

[AileTheAlien]

TLDR:
Underground belts' entrances should be directional, like how underground pipes work.

Long:
Contrary to existing forum threads(1)(2)(3), I think underground belts should have their magic removed, instead of changing the visuals to match the magic. i.e. They should be directional, like underground pipes. Their exits are already directed, and making their entrances act like pipes would make the game more consistent. The underground-belt's current behaviour feels either like a bug, when something goes wrong, or like a cheat or exploit, when you use it to your advantage. Hence, I suggest this change. :)

[Tekky]

I also don't think that underground belts should offer this feature, since it gives the impression of being an exploit. However, I still consider this feature to be very important. For example, it is the only way to build a lane balancer that is also input-balanced or for splitting the lanes of a belt onto seperate belts. Therefore, the game should continue to offer this feature, in my opinion. It just doesn't make sense that this important feature is provided by exits of underground belts. It should rather be provided by some other kind of entity.

Also, if splitters were redesigned to be input-balanced instead of only being output-balanced, then all of this would be less of an issue.

[Yoyobuae]

TLDR:
Underground belts' entrances should be directional, like how underground pipes work.

"Directional" doesn't quite mean what you explain in the rest of the post. They are both already directional: they can have open side facing north, south, east or west.

"Not allow input from the side" would be a more accurate TLDR.

[Rseding91]

No. They're the way they are now by design.

[ssilk]

Moved to won't implement, cause that changes the complete belt part of Factorio.
See instead viewtopic.php?f=80&t=32665 Make Underground Belt Magic More Visible