Newtoon Opia
Still searching for the ultimate map, this one centered around the ultimate interchange; no left turns, should work well with or without mods. Great for sandboxing and trying new things — especially with the prebuilt infrastructure thats free to maintain ?
Also works with Traffic Advanced AI and all that jazz.
update 4/27/2016: Was test playing the map earlier with –noWorkshop enabled, and felt it could use to be more efficient. So I tweaked the premade roads in the starting tile, its a bit more personal flavor and a lot less universal but works great by algorithms in the game. Except busses — no more sequential routing, but as always, feel free to change it if it suits you best (and share your thoughts via comment if it could benefit more than one). Uploaded a new picture with the new start tile.
update 4/28/2016: I’ll be making minor changes later today but I just want to stress, this city is designed to handle traffic and handle traffic is what it does. I uploaded a picture of my current city, still using the same starting tile, with a population of 25,000, no road changes, no public transportation (except for a pointless bus line thats there just to get my offices upgraded) and there are no traffic jams. I’ll upload a better picture when I get all my residential upgraded to high res later on but I know some people were confused by my previous picture, thinking that it was only for low residential housing.