Transpo Geekery: 4 way stops vs roundabouts

Mythbusters tests how many cars you can get through a roundabout vs a 4 way stop.

Mike the traffic engineer notes that 4 way stops are cheaper, but if you need to bump up the throughput, roundabouts are the winner.

Bike people like you and I are split on the safety of roundabouts for cyclists and pedestrians. Many people don’t like them. I’m okay with them for low speed roads, like the one we have in Santa Cruz, California where Center Street and Pacific Avenue come together near the wharf.

Via Carson Blume.

Update: I just noticed this post that goes into detail on the safety of roundabouts for pedestrians and cyclists via Streetsblog. Alex Inhan notes the Mythbusters video focuses only on level of service with only the briefest gloss on safety. Alex goes into more transpo geekery by talking about conflict points in the four way intersection vs a roundabout. “Conflict points” is a shorthand way of counting the number of places you need to look to avoid hitting something when crossing an intersection.


  1. A well designed roundabout and drivers who are used to a)roundabouts and b)cyclists is a safe alternative IMHO and experience. Think the design is not a problem since plenty of examples of good and bad practices in Europe. The car drivers being used (and taking into account) cyclists and pedestrians on the other hand… (sidenote:I’m belgian…)

  2. Apropos about experience with roundabouts & cyclists: I think that’s the case in Santa Cruz, too. The locals (drivers and cyclists alike) more or less know how to use the roundabout and how to operate their car or bike through it.

    We have heavy weekend tourist traffic, too, but on those days the traffic is so slow that bikes are the winner anyway.

  3. For driving efficiency, the round about wins hands down. I find them much nicer than stop signs.

    I have very little experience with them on a bike and can understand why they would make somebody apprehensive. It’s clear that in the case of bicyclists and pedestrians, design can make a big difference as well.

  4. I went through a series of roundabouts in Holland which had dedicated separated bike lanes, around the roundabout. My jaw dropped in disbelief when I saw them. I believe that the bikes were supposed to yield at the road points, but the drivers just stopped anyway for the bikes (the drivers are mostly all bikers also). At the time, I was just hanging out behind a group of locals, interested in how they ride. We were just rolling through the roundabouts. I was kind of giggling going through the roundabouts, and they must have wondered what was wrong with the American. The Dutch hate! to stop their bikes. The old ones weigh like 45lb, with one speed, and are a pain to get going again from a complete stop.

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