About 20 years ago, I had an ADC/Langenscheidt atlas of Pennsylvania–the whole state divided into a grid with one section on each page. The atlas was kind of quirky; it used an actual keystone shield to mark state routes and had most secondary SRs numbered as well. And it had some errors, too.
But perhaps the most unusual feature was that somewhere inside, it had a brief guide to interchange types. All of the example images were taken directly from the maps inside the atlas. As I recall, they showed a typical diamond, a trumpet, a full eight-ramp cloverleaf, and a four-ramp partial cloverleaf (folded diamond) that they called a "lyre interchange". Their "lyre" was basically a four-ramp parclo with all ramps in adjacent quadrants, like this...
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fbriantroutman.com%2FResources%2Flyre_interchange.png&hash=979b161cf8a6e4133e2e3ae7b575f999677b49b9)
The name seems to make some sense. That interchange probably looks more like a lyre than a "trumpet" looks like a something Miles Davis would play. But I have never, ever read or heard this term used anywhere else. A search for "lyre interchange" on Google comes up with only one result on the entirety of the Internet–and that item is irrelevant. Interestingly, a image search for "harp interchange" comes up with one relevant result from a highway project in Danzig.
So has anyone ever seen this term before?
Can't say I have, but it does look like a music lyre you'd afix to a clarinet or sax, so it's a good term to adopt, I suppose.
The term? nope.
The design? yes.
I like that term a lot better than "folded diamond." I'll try to remember to start using it.
Quote from: briantroutman on May 09, 2013, 03:07:03 PMThat interchange probably looks more like a lyre than a "trumpet" looks like a something Miles Davis would play.
The term
trumpet interchange originally comes from German (
Trompetenlösung). The typical drawing of a trumpet interchange which appeared in German technical literature in the 1930's shows one
Autobahn terminating at another, with both
Autobahnen curving toward the meeting point. The curves are the flares of the horn of the "trumpet" and the interchange layout, as sketched in plan, bears a far closer resemblance to the musical instrument than any American trumpet interchange. In fact, American trumpet interchanges (as found on public-authority turnpikes, for example) more closely resemble a layout whose German term translates to "one-sided access" and which in Germany was intended for use at service interchanges rather than motorway-to-motorway interchanges.