It's eight-way, although four of those eight are on/off-ramps.
US 3 and MA 4. Coordinates can be found by quoting my post.
Each segment of this "square" has six lanes. The left two lanes continue left (with traffic lights, so it's not a rotary), the middle two lanes continue straight, and the right two lanes turn right.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fmaps.googleapis.com%2Fmaps%2Fapi%2Fstaticmap%3Fcenter%3D42.622000%2C-71.365500%26amp%3Bzoom%3D17%26amp%3Bsize%3D400x400&hash=fd48d9e1738a770398d1fe1a852246894d996773)
I think it's closer in relation to a split diamond, but the edges are round enough that it appears to be more closely related to a roundabout (which is what it formerly was) than most split diamonds.
It reminds me a lot of the Hanger Lane Gyratory (https://goo.gl/nuEFvk) in London.
It looks like a beefier, squared-off version of a Rotary interchange similar (in concept) that one sees elsewhere in the Bay State. Other examples of rotary interchanges include the I-95/MA 129 interchange (https://www.google.com/maps/@42.5249642,-71.0809736,17.63z) in Wakefield or the I-95/East St./Canton St./Allied Dr. interchange (https://www.google.com/maps/@42.2226748,-71.1705587,17z) in Dedham
Similar in configuration to I-24's interchange with US 62 and US 45 in Paducah.
Quote from: PHLBOS on December 02, 2015, 04:50:03 PM
It looks like a beefier, squared-off version of a Rotary interchange similar (in concept) that one sees elsewhere in the Bay State. Other examples of rotary interchanges include the I-95/MA 129 interchange (https://www.google.com/maps/@42.5249642,-71.0809736,17.63z) in Wakefield or the I-95/East St./Canton St./Allied Dr. interchange (https://www.google.com/maps/@42.2226748,-71.1705587,17z) in Dedham
Prior to the US 3 widening project, this location was a traditional Massachusetts-style uncontrolled large circular rotary interchange, with the exception that the secondary roads are above the mainline instead of beneath (like at the I-95/MA 129 rotary interchange in Wakefield) . One of the reasons it was "squared off" as part of the US 3 reconstruction project was to accommodate minimum sight lines for the traffic signals that were installed at the time.
Given that all legs are signalized, this is best described as a split diamond.
Seems like the Circle Interchange with traffic lights.
Here's a link to the view of the Paducah interchange I referenced earlier. Upon closer inspection, it's a bit different, since the two routes are separate highways with two-way traffic.
https://www.google.com/maps/@37.054018,-88.6560661,16z
Then you have this at Washington CH, Ohio.
https://www.google.com/maps/@39.5266134,-83.4680985,16z