Multipexes that are only refered by only one route number

[oscar]

US 50 from MD Eastern Shore to DC is just called "50" even though there is US 301, I-595 and MD 2.

Can't really count I-595 since it's a hidden route, even with the open space for shields on just about every guide sign between the Beltway and Annapolis.

But it's curious to note the lack of US 301 shields on many of the guide signs.

Sirius traffic reports often refer to the multiplexed segment as "50/301."  That confuses me more than it should (sounds like route 5301), and I don't see what listeners would lose if the reporters just called it 50. 

[froggie]

As often as not, I hear WTOP refer to it as just Route 50 or US 50.

[Quillz]

I could be wrong about this, but I do believe the CA-44/89 multiplex through Lassen Natl. Park is signed only as CA-44, because CA-89 does not officially travel through the park's boundaries, even though it does exist on paper.

I was there a very long time ago and don't remember ever seeing CA-89 shields.

[national highway 1]

When US 191 was re-extended into eastern and southern Utah, south of I-70, it absorbed most of US 163, however the US 163 signs were left up there until several years later.

[Ian]

Bryant: These signs are not an unusual sight in New York. I think they're neat. My theory is that they made them that way to reduce wind drag.

my guess is that it is to save the costs of the raw materials.

Or both...

Yeah, those are both the primary reasons on why it's done. There is another one of this style on I-95 southbound in Peabody, MA as well.

[Scott5114]

They could save even more of they just omitted the arrows and made it a standard sign.