I’ve been playing Cities: Skylines lately–it’s a city building game along the lines of the old SimCity series. It’s a very complicated game and doesn’t have any tutorials, so I spent some time watching YouTube videos to learn how to play it. I noticed that the people making the videos always use a mod called Traffic Manager: President Edition to keep their traffic flowing smoothly. I decided to play without mods until I got a city to the final population milestone, and in doing so learned why that mod is so popular.
Here’s an illustration of a busy intersection with a vanilla Cities: Skylines traffic light. It’s a good thing there are no collisions in this game, or everybody would be dead. The game’s traffic lights have no separate left turn lights, so cars are trying to turn through opposing traffic from the opposite direction, and pedestrians pay no attention to the lights and just cross at will, further blocking things up. The lights also can’t be synchronized with each other, so things like the ubiquitous diamond interchange with two sets of traffic lights don’t work correctly.
I found that to compensate for this in the un-modded game, busy intersections needed to have only one light and no pedestrians, or no lights at all. The first thing I tried was the single-point urban interchange, shown above. It mostly works, although the light phases are wrong. There’s a pedestrian bridge just out of sight to the right, keeping them from clogging it up. I found that to get interchanges to really work well I had to use something which doesn’t actually exist in the real world: the double crossover merging interchange. Since fancy new interchanges are generally made by retrofitting an existing one, it’s not surprising none of these have actually been built. They work great in vanilla Cities: Skylines, though, where that’s not a concern and avoiding lights is vital.
