It looks like two node points really close together, possibly on top of eachother. Try deleting a node within the messy bit. Could be wrong.
I had this issue on American Road too. Some nodes of the highways were very far apart and the texture glitched like on your screenshot. Adding one or multiple nodes in between fixed it. I don't know why that happens though.
Perhaps your glitch is similar to mine? Please, ignore the black terrain as I though choosing option use PBR materials would of been a good idea, sadly it ruined whole level. Anyhow, there seems to be something awfully weird going on with decal roads as you can see from attached images. Despite terrain being perfectly level, decal road, for some unknown reason, appears to find very deep holes from terrain even such holes in reality are none to be found. Only solution for addressing these issues, which I have found to be sometimes working, is to raise and lower terrain, but not necessarily at the problem spot, but some distance away from the problem spot, then decal road magically gets repaired at the problematic spot. Certainly it would be interesting to find out methods to avoid such problems from occurring as it can be somewhat demotivating to use limited time available to repair something that should not occur in a first place.
I can see in that image you've got some pinching of the decal road on the inside of the corners. That could be the cause. Better to smoothen the corners and place it so it doesn't bunch up like that. Maybe that will help the outside of the corner not have this glitch. Otherwise, I find Beamng behaves a lot better if I export the heightmap, apply a small Gaussian blur on the image, and reimport it. That does smoothen the whole map though, so isn't for everyone. Particularly useful for large maps (8km or more), which often have issues. Unfortunately, the world editor is a labour of love. Either you accept your going to spend a lot of time in it, or make your maps very simple. It's part of the charm.
Sadly pinching is not causing this problem, in post which you quoted images were taken from modified Template map, this here is Mario kart track which I downloaded from forums, there is no terrain, just static object and there is no solution that I know for getting decal road going normally. After checking section with ground model debug tool, there was nothing out of ordinary that would of been easy explanation for this behavior. Map is Moomoo meadows from here https://www.beamng.com/threads/mario-kart-map-project-update-6-1-37-tracks.79000/ if someone would like to examine issue further, just place 250 meters of decal road from starting line onwards and decal road should fall trough like so. Certainly not normal for decal road to fall trough terrain or static mesh like that, sometimes it happens, sometimes it does not happen, what would be the trigger then? Perhaps we can learn the trigger if enough of these issues would be documented, or perhaps developers already have good idea what causes this situation, but it certainly is frustrating when nothing normal seems to help. -Edited post- When this glitch happens, I have seen often anchor point that is not sitting flush with the surface, those red anchor points are flush and selected white one is howering above a surface and there glitch starts, however Z value of anchor point is exactly as those red ones, so there must be some sort of program glitch. I have no capability to understand if this is meaningful in any way, but floating anchor point seems to appear quite consistently with decal roads falling trough the surface where they are supposed to be. Also I do not know which is cause and which is consequence, but I thought this is worth to mentioning as this issue has appearances of software bug all over him.
Sorry, way above my level all this. I generally find it t doesn't work, I try something else. I know that isn't helpful, but I wish you luck.
Hey Sorry, don't have time to focus on this rn so might be off point but I've been having a similar issue thats fixed itself when I toggle the "Over objects" checkbox. Seems that the decalroad anchors sometimes fall through mesh and reset to correct z-position when the "Over objects" is disabled and re-enabled.
