So are you just wanting to extend the road and use the same texture on all the parts? Like where you have the overlap?
Both suggestions from @rigoletto and @LazyVirus are GOOD…
I will show you what I do…for example this cobbled roadway…
A single extruded plane…used edge loops to break-up the plane into sections…and selected each one and separated by selection…each one has simple UV map rectangle…all the same…
Then in each one I applied the texture ( same for all ) like your texture…But I used Ctrl+T to add UV and mapping nodes before the texture which is tileable…but I changed the directions of each section in the UV editor to break up the pattern…By splitting and adding a UV i could scale the UV and eliminate the stretching…and vary the texture and get rid of the obvious tiling that happens on a seamless PBR.
Are you trying to blend materials or objects? I watched the video and you can do the same thing using a array, curve and shrink wrap modifier. You can blend the road material with the terrain using vertex colors and data transfer modifier.