The price of anarchy / The magic of roundabouts

Anarchy comes with a price.  Lawyers, economists and political scientists believe this.  This is what drives the congresses and senates and cabinets and presidents to make laws.

Traffic engineers also believe anarchy comes with a price.  They love to make streets one way, to close off cul-de-sacs, and install speed bumps, all in the interest of stopping people from doing what they otherwise would.  This keeps the punters on the main roads, and – in theory – keeps traffic speeds up.  For a longer dissertation on the price of anarchy, click here.

The price of anarchy, you might imagine, will be highest at an intersection. If I drive straight through, the effect on everyone else will be devastating.

To control this risk we are blessed with junctions guarded by the demeaning, bossy, stubborn traffic light.

I hate traffic lights. They treat me like a child. I hate, hate, hate, sitting there at the lights when there’s nobody coming, just because the system says so. If it can’t tell that it’s safe for me to go, then it’s not as smart as me. It has no respect for my time. Why should I respect it!?

Last summer, a major blackout took out the traffic lights right through the inner city, during peak hour, on one of summer’s hottest days. We were driving to the beach, and found that traffic flowed better than ever.

When pedestrian traffic crosses at an intersection, it intermingles and finds a way to get through. We don’t stop one flow of people to allow another group through. Is this an example of the price of anarchy? Or is it actually more efficient? I suspect the latter.

The best kind of intersections, then, are ones that allow people to go through whenever there’s a gap. That’s right. I’m a roundabout enthusiast. The roundabout cleverly slows people down and spins them out wider, creating gaps in the traffic flow an alert driver can easily get into. You never find yourself sitting at a roundabout waiting for the nanny state to tell you to go. It’s as efficient as it can possibly be.

But, some people hate roundabouts. In the USA, the first roundabout was built in only 1990. The locals hated it, and the trend has spread very slowly. There’s infinite blather railing against roundabouts in the vast inane tundra of the interwebs. But why? Are they so hard to use? I find it much easier to only give way to drivers on your right than to have to look in all directions when approaching a crossroads. It’s like anarchy, but cut-price. Total freedom, but total predictability and relative safety.

So people, why do you hate them so?? If you are a roundabout hater, please share your reasons below!

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Thomas the Think Engine is the blog of a trained economist. It comes to you from Melbourne Australia.

9 thoughts on “The price of anarchy / The magic of roundabouts”

  1. I love ’em. Even in high speed zones (eg the peninsular end of the Western Port Hwy, which has 4 big roundabouts in a 100km zone), the break in your travel seems much less than it would be if they were traffic lights.

    If you assume that traffic lights split the flow 50-50 each direction (most don’t really), then every second light will be red. One red light seems like a longer wait than two roundabouts.

    Or is it just psychological? Does the fact that you stop dead at a red light make it seem longer than the slow-but-still-moving roundabout?

    The only problem I can see with them is the case when there’s endless traffic coming from the right and you can’t get in. But this is inevitably broken by someone else exiting the roundabout in your direction, making a gap for you; thus the efficiency of the roundabout.

    Do people hate them cause they make you make you own decisions rather than relying on a signal?


  2. Great post.

    Here in Berkeley, and other parts of the US I have been to, many smaller intersections (that are prime candidates for a roundabout) have four-way stop signs. Traffic from each direction alternates, one car at a time. This is so ridiculous I am getting angry just thinking about it.

    Where roundabouts are installed, they also have four way stop signs!?!

    The beauty of the roundabout is in moderate traffic flows, where it allows two, three, or four cars through at a time from alternating directions.



  3. Thanks Rob, i know the road you’re talking about, and it works pretty well.

    Mac, i reckon you’re right about moderate traffic flows. Although, see the Arc de Triomphe above, which is chaotic but moves a lot of cars.

    ps. you are a sycophant. ;)


  4. Roundabouts are only good when they are actually round. yes, I’m talking about the wheel of death on Elizabeth/Royal pde. People say this is a bad one because of the tram running though it, but really the tram is good cause it breaks up the traffic cause every one has to give way to it. The problem is that it’s not very round and so no one knows where or how to exit. That being said, I’ve never seen a crash on it.

    On another note, on a recent trip to the Can I noticed that the Russle/Kings Ave roundabout is now being replaced by some under/over pass thing, so maybe they are only good till a certain size.

    As long as its not replaced with a 4 way stop it’ll be ok. Those things are shit.


  5. Enthusiastically agree – the fact they can control freeways full of holiday makers, and the also tiny backstreets, shows their versatility.

    As a point of interest (or as interesting as intersection solutions can really manage) – in Morocco, they run a slightly different system, where the people already in the roundabout give way to those entering. We were always in taxis, and those guys were clearly pros at negotiating these things, but it felt reasonably efficient, just terrifying for the uninitiated…


  6. I mus agreed- Roundabout of Death- Elizabeth St. People do know where to exit, however the roundabout is built so that in certain directions, you MUST change lanes to exit where you want. To break it down, pedestrians lights, pedestrian zebra crossing, trams on 2 different routes, and traffic approaching and exiting from 4 directions, each having more than 3 lanes.

    But not as bad as 4 stop signs,135.745076&sspn=37.134781,56.513672&ie=UTF8&hq=&hnear=Royal+Parade,+Parkville+Victoria+3052&ll=-37.801553,144.957572&spn=0.002026,0.003449&t=h&z=18


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