Sep 14, 2026

I have a weird soft spot for roundabouts. Maybe because I'm a software engineer and the roundabout strikes me as the simple, elegant solution while the traffic light intersection is the ad-hoc, over-engineered mess.

I don't have real expertise in civil engineering so take everything below with a grain of salt.

When two or more roads intersect, some system needs to dictate who can cross and who has to wait. The simplest is priority to the right but that doesn't scale. Traffic from all directions at the same time results in a deadlock.

The straightforward solution is traffic lights. But they come with several issues. Sometimes you wait at a red light although there is no conflicting traffic. Some intersections "patch" this problem by putting magnetic sensors into the road to detect waiting vehicles. If no vehicle on road A is waiting, traffic on road B can flow freely. But this causes another problem: Due to smaller metal mass, motorcycles and bicycles are often not detected, causing them to wait forever.

Another problem is the yellow light. In theory it should signal drivers to slow down. In practice you get the opposite. Drivers race to make it through at the very moment conflicting traffic is about to be released. Every problem can be fixed by piling on more complexity. E.g., add cameras or radar to penalize speeding after the fact.

But now consider the humble roundabout. It's solving all of these problems while being radically simpler. It has no active control mechanism and consumes no electricity. It's just a static structure, sitting there doing nothing. You never wait at a roundabout when there is no traffic. Of course when the road is busy you still wait but waiting always makes sense. Also, when approaching a roundabout you naturally slow down because you have to turn even if you're going straight.

Roundabouts come with this otherwise unused patch of land in the middle. Apparently, it has become common practice around the world to put some random art there, or a little green space, or a fountain, or a "welcome to this town" sign. I love that! It's such a delightful way to give some color to an otherwise mundane piece of infrastructure.

Here, look at some roundabouts from the roundabout database. Many have no street view or are simply boring, so I hand-picked a few I found curious (click on "Show an interesting one").