@Pickcle: In addition:
The service interchanges are interchanges connecting a highway to a regular road network. With these interchanges you need to connect '3-lane highways' to the highway ends of these interchanges, and a 'regular road of your own choice' to connect to the 'service road, or roundabouts' in these interchanges.

Thank you!

@Pickcle: To answer all four of your questions: All my interchanges are supposed to connect to three-lane highways (the basic highway you mentioned), as this is the default highway used in most maps.

So you're allready doing it correctly! :)

● Example
Basic Highway - System interchange - Service interchange - Service interchange - Basic Highway

Q1. Which highway should we use to connect each?
Basic Highway : 3-dir
System interchange : Stack Interchange 4-dir

Q2. Which highway should we use to connect each?
System interchange : Stack Interchange 4-dir
Service interchange : Cloverleaf Service Interchange 3-dir

Q3. Which highway should we use to connect each?
Service interchange : Cloverleaf Service Interchange 3-dir
System interchange : Stack Interchange 4-dir

Q4. Which highway should we use to connect each?
System interchange : Stack Interchange 4-dir
Basic Highway : 3-dir

The words may not be accurate because I use a translator.
First of all, I'm connecting everything to the Basic highway 3-dir.

Perfect. Thank you

@ Semyh: Ok, I did another update. Clipping should be gone now!

Apart from these two screenshots, most of which are fix, there are a few other very small bug. https://steamhost.cn/steamcommunity_com/profiles/76561198343202838/screenshots/

@ Semyh: I've updated the asset. It shouldn't show any more clipping of the road textures you mentioned. As this was one of my first interchange assets, I've also noticed some streetlights clipping through some roads. I've adjusted that as well.

To notice these changes you need to exit the game AND Steam. Then open Steam, and start your game again.

It's nice to meet someone who pays attention to every detail. I looked at each asset, they are really beautiful. :D

@ Semyh: I missed that! Once again thanks for the feedback! I'll adjust this ASAP and update the asset.

(In the meantime, if you have the 'Move it!' mod, you can pull back the 'one-lane roads' that are between the 'one-lane roads with barriers' untill it looks good again.)

Like this: https://steamhost.cn/steamcommunity_com/profiles/76561198030726872/screenshots/

I play with mods. Problems arise where sound barrier roads join other roads.( I use translate sorry :D)

@Semyh, thanks for the feedback!! just checked, but looks fine to me. Did you level the ground where you placed the interchange? Do you play Vanilla, or modded?

A great intersection. But there are a few minor bugs.I would like to share screenshots but I have no idea how to post them.
If you think about updating, sound barrier roads cause graphical bugs.