Talk:Roundabout interchange

Whitemud interchange
Okay, so maybe it's not a true volleyball, but it has more in common with that than a roundabout. One of the defining features is yield on entry. Triskele Jim (talk) 01:20, 3 June 2009 (UTC)

What is it called when the minor road gets separated into two roads heading opposite directions? A diamond interchange has two intersections and one bridge, a roundabout interchange has two bridges and you can drive in a circle on it. A roundabout with traffic lights is still a roundabout, just look at Groat Road and 118 Avenue, so can this still apply if one street is the ramps of a freeway? 117Avenue (talk) 04:33, 3 June 2009 (UTC)


 * My vote is "divided diamond," since it has more in common with a diamond interchange than a roundabout. No deflection, no yield-on-entry, no free-flowing circulating roadway. In my opinion, a circular intesection ceases to be a roundabout when it is signalized. No one ever calls Dupont Circle in Washington, DC or Columbus Circle in Manhattan roundabouts.


 * To me, it looks like they designed it to eventually allow a flyover for through traffic on 170th St., making it a true volleyball. That's especially apparent from this view: Expanding on Kurumi's analogy, perhaps this sort of half-volleyball should be called a spike interchange, since one player (the main road) says, "It's yours!" and the other has to deal with it.

--Triskele Jim (talk) 16:48, 3 June 2009 (UTC)

Is a divided diamond a real name for a type of intersection? True it isn't a true roundabout without the free-flowing circulating roadway, and I agree that the city is allowing room for future construction. But I would call Dupont and Columbus a traffic circle/roundabout. We could also look at the intersection as a diamond at-grade, with the Whitemud ramps as the minor streets. 117Avenue (talk) 23:56, 3 June 2009 (UTC)

Something isn't right...
This article doesn't sit well with me for some reason. The consensus on the rotary (intersection) and roundabout articles seem pretty clear and cited - rotaries are high speed traffic circles that have no place in modern traffic engineering because they are dangerous. They feature a lot of weaving, and very straight on and offramps, causing excessive speed. Modern roundabouts are good, because they force people to slow down while not backing up like a signalized intersection would. Now, I'd just turn these New England roundabout interchanges listed into rotary interchanges because that is precisely what they are, but looking at the British examples, they don't look like modern roundabouts at all and in fact, they look just like American rotary interchanges that are very out of style! What gives and what needs to be fixed where? Thanks, CSZero (talk) 04:20, 5 July 2009 (UTC)
 * Any input? Thanks, CSZero (talk) 04:00, 14 August 2009 (UTC)
 * Maybe a bit late to answer, but the "modern" roundabout switches the priority from the default "yield to right" (in the case of right hand traffic), which would prioritize the incoming traffic, to the circular traffic. So the incoming traffic has to wait, but the circle keeps moving. So you avoid a traffic jam on the circle that would quickly stall the whole intersection. I think any accident numbers don't have so much to do with that (mostly with people getting used to it or not), in both cases you avoid the often lethal high speed head-on or T-boning crashes like you'd get in a left turning crossing. Of course the "modern" ones don't look any different than the "old" ones, because the only difference are the added yield signs.--91.41.42.210 (talk) 12:09, 29 June 2021 (UTC)

Three-level stacked roundabout and Volleyball
commons and differences should be listed. --Hans Haase (talk) 10:48, 7 February 2013 (UTC)