A11 Angers Bypass 3 Level roundabout stack

[jackal]

I've always been quite impressed by the 3 level stack at M5 J11. (Obviously that's not 2 motorways meeting though)

It's not, but I'm sure a lot more traffic goes through J11 than goes through the French junction. J11 copes okay (IIRC, they've not even had to put freeflow left turns in) and so the french one should do more than okay.

[jackal]

Whodathunkit- the Italians are in on the act as well.

[Truvelo]

Whodathunkit- the Italians are in on the act as well.

But at least the roundabout is freeflow, even if there's a bit of weaving.

[Chris5156]

Whodathunkit- the Italians are in on the act as well.

But at least the roundabout is freeflow, even if there's a bit of weaving.

Looks like chaos to me!

Italians have some funny ideas about freeflow and roundabouts. This one's crazy!

[jackal]

There's a stacked roundabout on the R0 around Brussels. It's elongated like M25/A1(M), with a slip joining on the inside like M6/A34, and with unusual priorities like M621/A61. To add to the familiar feel, the Beligians seem to paint their dashes on D3+ roads so they line up with each other.

The march of the glorious stackabout continues!

[owen b]

There's a stacked roundabout on the R0 around Brussels

I used it quite frequently when I lived there and often wondered about it. It's the biggest roundabout I know of anywhere. It's so big it barely even feels like a roundabout when you drive round it. Why on earth is it so big? And it must be quite old - I think the Brussels ring dates to the 1970s and I'm supposing that junction does, too.

[jackal]

There's a stacked roundabout on the R0 around Brussels

I used it quite frequently when I lived there and often wondered about it. It's the biggest roundabout I know of anywhere. It's so big it barely even feels like a roundabout when you drive round it. Why on earth is it so big? And it must be quite old - I think the Brussels ring dates to the 1970s and I'm supposing that junction does, too.

It is part of a European variant of stackabout that is fully freeflow. See also the Italian example upthread. The size is presumably to make the weaving area longer and thus less intense. Despite that, the weaving must still be terrible when flows are heavy, but at least it's well away from the mainline. In that way it's sort of similar to a cloverleaf with C/D lanes.

[jackal]

The international stackabout saga continues with this example in Metairie, Louisiana. Spotted by Adam Froehlig, apparently.

[Peter Freeman]

Whodathunkit- the Italians are in on the act as well.

But at least the roundabout is freeflow, even if there's a bit of weaving.

Looks like chaos to me!

This looks like 'old-school' roundabout design, which I rather prefer over the standard UK geometry for roundabouts-over-motorways. Weaving, instead of crossing. But of course quite inadequate for higher volumes than these. And check out those short on & off ramps at both motorways!

[Peter Freeman]

Italians have some funny ideas about freeflow and roundabouts. This one's crazy!

I like it. Of course, this example's clearly for low traffic volumes, and it's in a rural area with little constraint on land-take.

Internal ramps, rarely seen, eliminate two of the four conflict points of the standard roundabout design. In this example, the loop-road elongating the roundabout south-westwards and crossing over the motorway by a bridge that has been displaced south-westwards, diverts traffic away from two crossovers that would otherwise exist. But I suppose, in general, the pro's are outweighed by the con's such as longer path length.

[Owain]

Whodathunkit- the Italians are in on the act as well.

But at least the roundabout is freeflow, even if there's a bit of weaving.

Looks like chaos to me!

Italians have some funny ideas about freeflow and roundabouts. This one's crazy!

Pah!.... that's nothing. Check out this baby. It isn't a GSJ, but it is entirely freeflow, and enormous. Also, as it's in the middle of nowhere, there is hardly any traffic on it. It's completely unnecessary! And I usually got lost on it.

[Peter Freeman]

Pah!.... that's nothing. Check out this baby. It isn't a GSJ, but it is entirely freeflow, and enormous. Also, as it's in the middle of nowhere, there is hardly any traffic on it. It's completely unnecessary! And I usually got lost on it.

That's a good one! Check out this weirdo.