More circles!

I was looking for utopian city layouts the other day and came across an interesting one on a website which is now down, so I won't link to it. I did save this image from it that demonstrates the basic layout:

It's funny that utopian cities always seem to be circular, anyway this one seemed interesting mainly because it has zoning and could connect a bunch of these circular hubs together to create a city of circles. Of course, I only actually made one city in game because I can't seem to stick with any one idea for very long. I implemented the circles on the outside ring as roundabouts and I was going to use each roundabout to connect to another circle like in the small diagram top right, but I never got around to it.

Here's what the final product of one of these circles looks like in game:

I like this circular design because the roads are for the most part fairly straight, allowing zoning to be more efficient. High density commercial and office in the middle, then a ring of high density with the rest being low density. There are squares of low density commercial/schools/park/city services as well. Here's a picture of the zoning:

Of interest, there is no road connection to the rest of my city. The industrial area on the right is fed by a cargo harbour on the river, and the very centre of the circle has a passenger train station with tracks immediately going underground, which makes it a kind of high capacity subway using trains rather than the metro system.

As you can see below, the tracks go right underground. Also you can see that this station is insanely popular, given that there are no roads to connect with the rest of the city, which gives it an automatic 100% efficiency:

There is also one bike path connecting the outside of the circle to the rest of the city. It's also fairly well travelled:

While the need for industry does somewhat break the circle pattern, if one was ambitious, one could make a connecting circle entirely for industry. Overall this circle design has around 12,000 people, but could be more as the average building level is not very high. This is a nice-looking design pattern, especially if you stick a few tall landmark buildings in the centre like I did. I think this is my most successful experiment so far, and if I run out of other ideas I'd like to take this one and try to make an entire city out of these connecting circles like in the design at the top.