This reminds me first 3d era map mods... in 2002 lol
Pretty much this. No offense, I appreciate you try to do something in GTA 3, since it's very overlooked and underappreciated game at this point, but this mod is just... Lazy, or unfinished, to say at least. Ramps block certain lanes, the extra road sticks out like a sore tooth, and on top of that, there are trees popping up from its surface. I've been having lots of fun with MEd years ago, and believe me when I say, you can do much, much more with all these stock models if you'd really want. All that being said, you still wouldn't be able to add a new road nicely connecting to already existing one. Not without some fun in 3ds Max or ZModeler that is.
Age of so simple and unpolished mods has come to an end years ago, and there's really no reason to go back there. Neither for creators nor their audiences.