Ah OK. I understood that the one on the right was a road that you had created...
Modifying a road already made is possible but more complex because you must extract its components (3D mesh and textures) first and then edit them. In your case you only need an image editor (photoshop, gimp or similar). To extract all these things, you can use this mod: https://steamcommunity.com/sharedfiles/filedetails/?id=1845697704&searchtext=network
Once you've extracted everything and edited the textures, you can re-import everything into the editor, as if it were your own creation. Follow the video explaining the steps
Of course, you won't be able to share it on the WS without the author's permission, but that's another matter.
Modifying a road already made is possible but more complex because you must extract its components (3D mesh and textures) first and then edit them. In your case you only need an image editor (photoshop, gimp or similar). To extract all these things, you can use this mod: https://steamcommunity.com/sharedfiles/filedetails/?id=1845697704&searchtext=network
Once you've extracted everything and edited the textures, you can re-import everything into the editor, as if it were your own creation. Follow the video explaining the steps
Of course, you won't be able to share it on the WS without the author's permission, but that's another matter.