Here's a 100 lane road I made a while back. It's technically functional but has a ton of visual bugs and will destroy your pc. I haven't seen anyone actually make a city with it yet (besides in Houston), and my laptop is nowhere near powerful enough to simulate this.

If you have the time, I would love to see someone post a video of this in action! https://steamcommunity.com/sharedfiles/filedetails/?id=3262532151