A walkable metro-based city with density circles

The goal of this site is catalogue some of the experiments I've done in Cities:Skylines with the hope of inspiring others. I lack the patience to follow through any of these designs, so I'm going to post up some of the designs and small-scale experiments I have done, with the hopes that others may find them interesting, and use these experimental cities to make something a lot more interesting than what I've been able to create.

For this post I'll focus on a city I started using the concept of density circles around mass transit. To make mass transit the most effective, ideally you want everyone in a city to live fairly close to something like a metro system. So to do this, I built my city as a set of circles with a radius of 400m, which works out to 500 squares in the game.

In the centre of each circle is a metro station, with bus routes looping around the circles to take people into the denser centre, and to a metro station. Here's a picture of the transit routes:

As you can see, the metro is heavily used, just under 2,000 trips/week for a city of 20k people is pretty good. The efficiency of these metro lines is also crazy. The main line is 100%, and the two connecting lines which you can see in blue and white above are both above 95% efficiency. So almost anyone who can take the metro, does.

Other than the metro-centric design of the city, the other main feature is the decreasing density from the centre of each circle. As you can kind of see in the picture below, the main street which cuts the circle in half is all zoned commercial, with the two halves closest to the centre as dense commercial.

There is then an inner cross of high density residential buffered by some offices. The key to this is the road pattern you can see below. The roads outside of the inner cross are for low density and their pattern does not matter. The main inner cross, however, ensures that high density residential is closer to the metro station and closer to the high density commercial.

My goal was to create an entire city of these circles, but I gave up after 4, which gave me a population of 20,000. As I said earlier, I lack follow through! I mainly gave up because I wanted to try out other ideas.

One interesting problem I had was traffic coming off the highway having to entirely funnel onto one road that led into the traffic circle you can see above on the left. To fix this, I made the on and off ramps go directly to and from the traffic circle, which dramatically increased traffic flow.

As you can see in the picture above, I also separated out the industrial areas associated with each circle in order to avoid pollution problems. I also attached the circles with bike paths which went through the industrial areas.

Overall I deemed this experiment a success, as it generated huge metro usage and created a pleasant city layout.