@LemonsterOG Thanks, happy New Year to you as well!

@Spartelfant Thanks for the reply. I'm going to test it with other road types and see what happens.

Happy New Year!

Hmm that's odd. Perhaps it has to do with the way I constructed this intersection:

What I did was first build the tunnel (10u long from ground level to -12m, then another 10u long from -12m to ground level). Then I laid down the 20u road across the tunnel (start from 10u away, because if you start in the middle it will want to snap to the road in the tunnel).
Once that's done, put down the slip roads and they will cause the tunnel entrances to move closer to the road at ground level.
Didn't even need Road Anarchy or any other mods. Of course you still need TM:PE to disallow left turns if you want to, though you could leave it as-is if there isn't too much traffic.

Building it this way makes the intersection more compact than would otherwise be possible, but perhaps this causes issues with certain road types. That's my best guess anyway, unfortunately due to long-term health issues I'm unable to test this in-game myself.

I experienced something odd with this intersection. I needed the underpass to be the vanilla 4 lane tram road. When I upgraded the existing underpass to the tram road, it threw infinite object errors so I had no other way around it but to force quit the game. I do use a lot of mods, but have for months without errors, so I'm not sure if it's a mod issue or one with this asset.

If you have an area with a grid(like) layout with several of these intersections, then traffic can still turn left by going straight first and then turning right three times. It's not the shortest route, but traffic keeps flowing better, so it is faster.
In fact UPS uses this tactic as well. Even though they could turn left, they don't. Not having to turn through oncoming traffic (which involves a lot of waiting), combined with right turns that don't require waiting for a traffic light means they travel more distance, but do so in less time.
This intersection has the added benefit of through traffic flowing uninterrupted in two directions at the same time.

Why would you have an intersection that completely eliminates left-turn traffic? Doesn't that make it very situational? Like maybe at the end of a block?

@CA$H THE GREAT Traffic is not supposed to make left turns in this intersection, only straight through or right turns. You will need a mod such as TM:PE (linked in the description) to disallow left turns. Or if you only have light traffic, you could decide to allow left turns.
The idea of this intersection (and disallowing left turns) is to have a small footprint and allow a good flow of traffic.
So if you have a situation where you have a lot of straight through traffic and can do without left turns, this intersection (in my experience) performs better than a roundabout (where every direction has to merge with every other direction). Unless you use a roundabout with slip lanes for right turns, but that takes up more space than this intersection.

I don't understand how traffic makes left turns in this intersection.... Seems there would still be conflict there in crossing oncoming traffic at some point, would there not?

So good!

cool

What I did was first build the tunnel (10u long from ground level to -12m, then another 10u long from -12m to ground level). Then I laid down the 20u road across the tunnel (start from 10u away, because if you start in the middle it will want to snap to the road in the tunnel).
Once that's done, put down the slip roads and they will cause the tunnel entrances to move closer to the road at ground level.
Didn't even need Road Anarchy or any other mods. Of course you still need TM:PE to disallow left turns if you want to, though you could leave it as-is if there isn't too much traffic.

I use this type of system also. I can't ever seem to get it this compact.