# Safety of Multi-lane roundabouts **URL:** \ **Category:** Factual Questions\ **Created:** [November 8, 2013, 8:49pm UTC](https://boards.straightdope.com/t/safety-of-multi-lane-roundabouts/673453 "2013-11-08T20:49:01Z")\ **Posts on this page:** 11\ **Page:** 3
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [November 12, 2013, 4:26am UTC](https://boards.straightdope.com/t/safety-of-multi-lane-roundabouts/673453/41 "2013-11-12T04:26:50Z")
> [@Motorgirl](#): > > That database doesn’t seem to list any of the ones I go through every week, as any type. > > All are in Cambridge, Medford and Arlington, and none seem to be listed in that db. I’d say that db is very incomplete. Well, when I said it was a bit outdated, I was, shall we say, understating things a bit. There’s less than 2000 entries in the db, but I’ve seen estimates of about twice that many roundabouts in the US. So it’s quite a bit behind and they’ve disabled user updating it. However, I’ve sent them email with some additions and they made them after a week or so. If you’re really interested, perhaps you could send them info on the roundabouts in your area. ---
**Author:** ![Motorgirl](https://avatars.discourse-cdn.com/v4/letter/m/e36b37/32.png) [@Motorgirl](https://boards.straightdope.com/u/Motorgirl)\ **Post date:** [November 12, 2013, 7:55pm UTC](https://boards.straightdope.com/t/safety-of-multi-lane-roundabouts/673453/42 "2013-11-12T19:55:00Z")
> [@Maserschmidt](#): > > [http://www.frcog.org/pubs/transportation/Roundabouts/Roundabout\_FAQ\_FINAL.pdf](http://www.frcog.org/pubs/transportation/Roundabouts/Roundabout_FAQ_FINAL.pdf) > > This doc from here in the suburbs seems to suggest that Fresh Pond is a rotary but not a roundabout… There’s a lot of text there - can you summarize which points lead you to conclude Fresh Pond is not a roundabout? ---
**Author:** ![Maserschmidt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/maserschmidt/32/18829_2.png) [@Maserschmidt](https://boards.straightdope.com/u/Maserschmidt)\ **Post date:** [November 13, 2013, 1:43am UTC](https://boards.straightdope.com/t/safety-of-multi-lane-roundabouts/673453/43 "2013-11-13T01:43:57Z")
> [@Motorgirl](#): > > There’s a lot of text there - can you summarize which points lead you to conclude Fresh Pond is not a roundabout? They view rotaries as an impediment to flow, not a benefit - have you ever merged onto Fresh Pond at 5:30 PM!? A little more seriously, they make the distinction with rotaries being much larger, and to my point above, detrimental to flow during heavy traffic. So with roundabouts being typically smaller, and rotaries being larger, I hazarded a guess. ---
**Author:** ![Motorgirl](https://avatars.discourse-cdn.com/v4/letter/m/e36b37/32.png) [@Motorgirl](https://boards.straightdope.com/u/Motorgirl)\ **Post date:** [November 13, 2013, 2:40am UTC](https://boards.straightdope.com/t/safety-of-multi-lane-roundabouts/673453/44 "2013-11-13T02:40:35Z")
> [@Maserschmidt](#): > > They view rotaries as an impediment to flow, not a benefit - have you ever merged onto Fresh Pond at 5:30 PM!? What am I, stupid? Hell no! 😃 But can you imagine what that intersection would look like as a signaled intersection? Probably a lot like the horror half a mile away at Rt 2 and 16. > [@Maserschmidt](#): > > A little more seriously, they make the distinction with rotaries being much larger, and to my point above, detrimental to flow during heavy traffic. So with roundabouts being typically smaller, and rotaries being larger, I hazarded a guess. Thanks, I think I understand your conclusion, but I honestly do think that both of the Fresh Pond rotaries help flow rather than hinder it, plus they’re pretty darn small. So I guess I just come to a different conclusion than you do. Let’s settle our differences with a race from Alewife to Mt Auburn via Fresh Pond! ---
**Author:** ![CoastalMaineiac](https://avatars.discourse-cdn.com/v4/letter/c/e8c25b/32.png) [@CoastalMaineiac](https://boards.straightdope.com/u/CoastalMaineiac)\ **Post date:** [November 13, 2013, 4:02am UTC](https://boards.straightdope.com/t/safety-of-multi-lane-roundabouts/673453/45 "2013-11-13T04:02:49Z")
> [@Motorgirl](#): > > What am I, stupid? Hell no! 😃 But can you imagine what that intersection would look like as a signaled intersection? Probably a lot like the horror half a mile away at Rt 2 and 16. > > Thanks, I think I understand your conclusion, but I honestly do think that both of the Fresh Pond rotaries help flow rather than hinder it, plus they’re pretty darn small. So I guess I just come to a different conclusion than you do. Let’s settle our differences with a race from Alewife to Mt Auburn via Fresh Pond! If you are talking about these rotaries, one of the biggest things I can see missing is the lack of pavement markings inside the circle, and directional arrows before the circle. A _modern_ roundabout would have the lanes clearly marked. Someone already linked to a perfect example of the modern version, [here](https://maps.google.com/maps?q=columbus+ohio&ll=40.02921,-83.161231&spn=0.002736,0.004672&oe=utf-8&client=firefox-a&hnear=Columbus,+Franklin,+Ohio&t=h&z=18). There are also pavement markings in advance of the roundabout that tell drivers which lanes go left, straight, and right, and so long as you pay attention to them, no lane changes within the roundabout, either on entry or on exit, are necessary. ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [November 13, 2013, 12:57pm UTC](https://boards.straightdope.com/t/safety-of-multi-lane-roundabouts/673453/46 "2013-11-13T12:57:55Z")
> [@CoastalMaineiac](#): > > If you are talking about these rotaries, one of the biggest things I can see missing is the lack of pavement markings inside the circle, and directional arrows before the circle. One near me that I use sometimes [has that problem](https://maps.google.com/maps?q=ann+arbor+skyline&ll=42.301808,-83.781093&spn=0.000923,0.001489&t=h&z=20). No pavement markings in the circle, and worse, coming from the North two lanes are clearly marked as continuing South, but when you get to the other side of the circle, there’s suddenly only one lane. There’s a merge sign, but by the time you get to it, you have to already be merging. And of course because it’s a roundabout, you’ve got a lot of other things to look at, and you’re zigging and zagging as it is, so you don’t see it until you’re right on top of it. ---
**Author:** ![Motorgirl](https://avatars.discourse-cdn.com/v4/letter/m/e36b37/32.png) [@Motorgirl](https://boards.straightdope.com/u/Motorgirl)\ **Post date:** [November 13, 2013, 2:52pm UTC](https://boards.straightdope.com/t/safety-of-multi-lane-roundabouts/673453/47 "2013-11-13T14:52:32Z")
> [@ZenBeam](#): > > One near me that I use sometimes [has that problem](https://maps.google.com/maps?q=ann+arbor+skyline&ll=42.301808,-83.781093&spn=0.000923,0.001489&t=h&z=20). No pavement markings in the circle, and worse, coming from the North two lanes are clearly marked as continuing South, but when you get to the other side of the circle, there’s suddenly only one lane. There’s a merge sign, but by the time you get to it, you have to already be merging. And of course because it’s a roundabout, you’ve got a lot of other things to look at, and you’re zigging and zagging as it is, so you don’t see it until you’re right on top of it. Tsk tsk. Apparently that’s NOT a roundabout and you’re not allowed to call it that. No lane markings, of course. ---
**Author:** ![CoastalMaineiac](https://avatars.discourse-cdn.com/v4/letter/c/e8c25b/32.png) [@CoastalMaineiac](https://boards.straightdope.com/u/CoastalMaineiac)\ **Post date:** [November 13, 2013, 4:40pm UTC](https://boards.straightdope.com/t/safety-of-multi-lane-roundabouts/673453/48 "2013-11-13T16:40:45Z")
> [@Motorgirl](#): > > Tsk tsk. Apparently that’s NOT a roundabout and you’re not allowed to call it that. No lane markings, of course. I believe it fits the definition of a plain-old roundabout, just not a _modern_ one. At least, according to a road engineer I talked to once. ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [November 13, 2013, 5:54pm UTC](https://boards.straightdope.com/t/safety-of-multi-lane-roundabouts/673453/49 "2013-11-13T17:54:23Z")
> [@Motorgirl](#): > > Tsk tsk. Apparently that’s NOT a roundabout and you’re not allowed to call it that. No lane markings, of course. That _is_ a roundabout, at least in official Ann Arbor parlance. It is absolutely _not_ a traffic circle, again in official Ann Arbor parlance. I don’t believe Ann Arbor uses the term “rotary” at all. ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [November 13, 2013, 5:57pm UTC](https://boards.straightdope.com/t/safety-of-multi-lane-roundabouts/673453/50 "2013-11-13T17:57:56Z")
> [@CoastalMaineiac](#): > > I believe it fits the definition of a plain-old roundabout, just not a _modern_ one. At least, according to a road engineer I talked to once. It’s six years old, opened in the summer of 2007. ETYA: [Cites](http://blog.mlive.com/annarbornews/2007/09/third_maple_road_roundabout_se.html) for this post and my previous one, in case anyone cares. ---
**Author:** ![Maserschmidt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/maserschmidt/32/18829_2.png) [@Maserschmidt](https://boards.straightdope.com/u/Maserschmidt)\ **Post date:** [November 16, 2013, 1:46am UTC](https://boards.straightdope.com/t/safety-of-multi-lane-roundabouts/673453/51 "2013-11-16T01:46:48Z")
> [@Motorgirl](#): > > Let’s settle our differences with a race from Alewife to Mt Auburn via Fresh Pond! No chance. I love Mt Auburn, especially in the fall, but I’m only approaching it via Watertown Square. 🙂 [Previous page](https://boards.straightdope.com/t/safety-of-multi-lane-roundabouts/673453.md?page=2)