Game developer rasjar presented their own custom traffic system they will use in their driving game powered by Unity. It supports right- and left-hand side traffic, multiple lanes with random lane switches, and one-way and bi-directional roads.
"I'm working on a driving game and empty streets are boring so I spent some time building my own traffic system," the developer said on Reddit. If you have any ideas what else they could add, feel free to share them there.
According to rasjar's other post, the game will be an isometric top-down racer, the demo of which you can try here.