I am a big fan of Stephen Dubner and Freakonomics. Recently, I dialed up the Freakonomics podcast, just looking for something to listen to while I sat in the hot tub. I came across an episode about roundabouts. You know, traffic circles? These are not to be confused with “rotaries,“ which are very large traffic circles and not the subject of this post. I’m talking about the smaller ones that are very common in England and other parts of Europe, and, as it turns out, quite common in one particular city in Indiana — but that’s not relevant. Of course, neither was the hot tub comment.

A Roundabout

I don’t know why I chose this particular podcast episode. It’s not a subject that I’m interested in. for any other reason. I guess I was just curious why there might be a Freakonomics podcast on the subject. I went with my instinct, and I’m glad I did. I’m learning that I need to do this more often. My mind was spinning on Understanding On Purpose, I listened to something that I thought was completely unrelated, and my mind made some unexpected connections.

I learned that roundabouts have a lot of advantages over intersections with traffic signals. They have a few disadvantages, but not seemingly enough to justify how uncommon they are in the United States.
For instance…

Traffic Signals vs. Roundabouts

Collisions at traffic signal intersections are four times more deadly (fatal) than collisions at roundabouts. The flip side is there are slightly more fender-benders at roundabouts.

Roundabouts are considerably less expensive to build and maintain, largely due to the surprising amount of engineering that goes into a traffic signal intersection. Traffic signals require some pretty advanced structural dynamics to allow them to withstand weather conditions and errant drivers, and they contain a lot of pretty sophisticated electronics and other hardware just to function. Roundabouts, on the other hand, require none of that — just mainly the same materials and techniques that are used to build roads.

Roundabouts are significantly better for the environment, even regardless of the aforementioned engineering and electronics, because traffic signals inherently require that automobiles spend a lot of time sitting and idling, whereas roundabouts do not.

Traffic signals are designed to be at their most efficient during peak traffic hours: a few hours a day. Roundabouts are however more efficient at moving traffic in the aggregate. The downside to roundabouts, here, is that they can get clogged when traffic is very heavy.

Traffic signals are typically not designed for their aesthetics. Roundabouts tend to have a park-like look about them.

One down-side to roundabouts is that they tend to become impractical in areas where there are a lot of close intersections, like in some parts of cities. They don’t take up more real estate than the average traffic signal that they tend to replace, but they do use more than very small intersections.

Human Factors

But why am I blogging about roundabouts at Understanding On Purpose? It’s because of the differences in the human factors associated with traffic signal intersections versus roundabouts.

Some examples…

Traffic signals work as well as they do because people voluntarily comply with rules (laws).  Roundabouts work because people collaborate.

At a traffic signal, we trust that other drivers will comply, so that we can pay less attention to the other drivers. When the light is red, we wait our turn and watch other drivers drive by (or check our phones). At a roundabout we must pay attention to other drivers in order to get through the intersection.

At a standard traffic signal, traffic inherently opposes other traffic; either running in the completely opposite direction, or completely perpendicular. At a roundabout, people get to their destination by blending with one another.

What’s the point?

If you’ve read this far, you may feel like you’re on a roundabout yourself. What’s my point?

It’s this: Many conversations have the qualities of traffic signals — where people just want to get past each other and get on their way. Better conversations tend to have some of the qualities of roundabouts — where people voluntarily work together to achieve a common goal. And ironically it’s the latter in which we retain a greater degree of personal agency.

I offer this as something to consider, in a roundabout way, the next time you’re in a conversation.