It won’t work for a four way stop with lots of traffic, it will just make things worse actually.

smallerfish 4 days ago | parent | next [-]

What is the traffic flow rate in an intersection with a 4 way stop? For single lane, since only one vehicle can be in the intersection at once, and probably takes _at least_ 5 seconds to start from stopped and cross the intersection, I'm guessing in the 10-12 region per minute best case, so maybe 600 an hour?

Now if you convert it to a mini roundabout, you can have at least two vehicles in the intersection at all times. I fail to see how it wouldn't be an improvement.

	▲	seanmcdirmid 4 days ago \| parent [-]
		I think you are making lots of assumptions here, like when I say space, I guess you assume it is still perfectly flat and the roads are perfectly aligned? The particular four way I'm thinking about, which really should be a traffic circle if they could blow away some houses, is 65th NW and 3rd in Seattle: https://maps.app.goo.gl/7KBhbJ9oAvDwrfGN8 So notice we already have problems in a bad alignment of 3rd, and 65th is basically a steep grade, even coming up form the west. I think you could put a circle in if it were flat, even with the bad alignment (or maybe because of the bad alignment), but this hills make a non-starter. It also gets enough traffic that I'm pretty sure they are just going to put a stop light up eventually.

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ndsipa_pomu 4 days ago | parent | prev [-]

Why not?

Here in the UK, we've got lots of roundabouts from tiny mini-roundabouts (some of which have four junctions) that could easily fit almost anywhere, all the way to gigantic multi-roundabout junctions (https://en.wikipedia.org/wiki/Magic_Roundabout_(Swindon) ).

I can't think of a situation where it's more efficient to have four vehicles all stop at a junction (busy four way stop) vs a roundabout which will allow one or two vehicles to join the roundabout without having to stop.