Everybody knows what a cloverleaf looks like — but could you identify a volleyball, a double trumpet, or a “spooey” if you drove on one in the course of your highway travels? These are among the distinctive designs that transportation engineers have conjured up to keep traffic flowing and motorists headed in the right direction when major roads intersect.

For your driverly edification, we’ve compiled photo examples of more than 2o different kinds of strange and delightful highway interchanges found both here in the US and abroad. In fact, right now stimulus dollars are being spent t0 build or upgrade many interchanges into one of these forms.

See Part 2 (with 11 more interchanges).

The Turbine – A “free-flow” style of exchange like the cloverleaf — that is, no traffic signals or intersections. This example is in Florida, at the junction of I-75 and I-4:

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The Cloverleaf – a classic, but it has fallen into some disfavor among traffic engineers because it causes weaving because cars are entering and exiting in the same lane. It also doesn’t handle large traffic volumes as well as some other configurations (for example, stacks).

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The Stack - A vertically layered arrangement of highways and connecting elevated ramps. The number of levels varies and go as high as six (though three and four are more common). Stacks are expensive to build but very efficient for high traffic volumes. This example is in Shanghai, but there are many stacked interchanges in the US:

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The Lofthouse: A roundabout over two grade-separated highways. Less expensive than than a stacked interchange, but also has much lower capacity.

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The ParClo – Or Partial Cloverleaf, a very popular design for places where interstates meet larger state and local roads. Depending how the loops and ramps are configured, a parclo is classified as either an A or a B and a number 1 through 4. This is an A-4:

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The Butt – A highly gluteal variety of the parclo. This example is in Germany:

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The Clovermill – A partial cloverleaf with turbine-style flyover (or, elevated) ramps:

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The Cloverstack – Combines elements of cloverleaf and stack designs. This rather feminine example  is in Eastern Europe:

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The Spaghetti Bowl – When we get into the realm of shapes and patterns that seem to be describable only by chaos theory or string theory. Spaghetti is a global phenomenon these days.

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Classic Diamond – A simple and venerable design. It doesn’t eat up much land, but it can easily get backed up. This one is in Kentucky, near Louisville. (There is also a “Diverging Diamond” variant that involves driving on the “wrong” side of the road — for an example see this video showing one that’s being built in Utah.)

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The Spooey – The Single Point Urban Interchange (or, SPUI) is very compact and one of the best choices for tight spaces in cities. Unlike the diamond, it sends all traffic through one signal. The disadvantages of this arrangement are that it can be confusing to some drivers though, and it tends to be inhospitable to bikes and pedestrians. (See a visualization of a SPUI here.)

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The Braid – This Maryland interchange is a stack design, but what’s unique about it is that the north and southbound segments of I-95 and east- and westbound segments of I-695 are actually braided over each other briefly in the middle of the interchange. (See a diagram here.)

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SEE Part 2 of Crazy Highway Exchanges

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ALSO CHECK OUT ON INFRASTRUCTURIST:

HA! AMUSINGLY DEFACED STREET SIGNS

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CELL PHONE TOWERS PRETENDING TO BE TREES

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We’ve credited photos when the information has been available. Many are in the public domain. Satellite images from Google maps, Terraserver and Microsoft. If we missed any credits, please let us know.

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Top photo: GSGeorge