Interstates and US routes w/o a duplex within a state

[Bickendan]

US 97 in California doesn't have any concurrencies, I believe.

Isn't it concurrent with Business I-5 on its southernmost mile?

It is. Just had to double check that CA 265 wasn't also in on the action (north half of Bus I-5 only).

True, but are we counting business routes, considering they aren't technically state highways?

Yes, because OR 99 and US 30 function as I-5 and I-84's respective business routes.

[wriddle082]

South Carolina has I-20, I-385, I-520, and I-526.

It seems that every US route in the state has a concurrency, which is easy to understand since there are so many of them.  No county in SC is served by fewer than two US routes.

[Darkchylde]

As far as US highways go, in Missouri, looks like US 56 and 275 are the only ones with no overlaps whatsoever.

As for Interstates, we have I-170, I-270 and I-670 running alone, by the looks of it.

[golden eagle]

In California, I-8, U.S. 6, U.S. 199, U.S. 101 (pretty sure about this).

Doesn't US 101 have a concurrency with CA 1 somewhere? I seem to recall having seen one signed somewhere west of L.A. GMaps shows one in Ventura, maybe it was there.

Yes, but not with any U.S. or Interstate route. I thought this thread was only looking for those.

It's fine if the interstate or U.S. highway is concurrent with a state route. Because there are so many state routes, I intentionally left them off.

[CNGL-Leudimin]

Then every US and Interstate route in CA apart from US 50, US 95, I-5, I-10, I-40 and unsigned I-305 .

Damnit, forgot I-80 and I-580...

[Rover_0]

Utah:

I-215 and US-89A

That's about it, unless you ignore unsigned duplexes and take UDOT's word that US-189 "ends" in Heber City and "shadows" along US-40 and I-80.

[rickmastfan67]

PA (off the top of my head)

I-95 (forgot about the short segement that duplexes w/US 322)
I-176
I-276
I-283
I-476

You can add I-86 (if you don't count the segment that comes into PA that NY maintains and has NY-17 on it), & I-579 to that list.

[bugo]

US 271 in Arkansas is the only one that I can think of.

The northernmost 500 feet are duplexed with Truck AR 255.

[robbones]

US 271 in Arkansas is the only one that I can think of.

The northernmost 500 feet are duplexed with Truck AR 255.

The original poster said a few threads up that state roads don't count

[PHLBOS]

PA (off the top of my head)

I-95 (forgot about the short segement that duplexes w/US 322)
I-176
I-276
I-283
I-476

You can add I-86 (if you don't count the segment that comes into PA that NY maintains and has NY-17 on it), & I-579 to that list.

Assuming that the two PA segments of I-86 are considered to be one highway/route; it can not be considered a route without a duplex.

OTOH, you're right regarding I-579 and I've since modifed my earlier list.

[Pete from Boston]

PA (off the top of my head)

I-95 (forgot about the short segment that duplexes w/US 322)
I-176
I-276
I-283
I-476
I-579

MA

I-84 (though it was once co-signed w/MA 15 many years back)
I-90
I-190
I-290
I-295
I-391
I-395

I would say 495 as well.  There's not really a time one is on both 495 and 140, even though 140 flanks 495 for a short stretch. 

[PHLBOS]

MA

I-84 (though it was once co-signed w/MA 15 many years back)
I-90
I-190
I-290
I-295
I-391
I-395

I would say 495 as well.  There's not really a time one is on both 495 and 140, even though 140 flanks 495 for a short stretch. 

It is my understanding that the primary premise of this thread is Interstates and US routes that have no other shared route along its corridor whatsoever within a state.  By that definition, I-495 in MA would not meet the OP's criteria due to its short duplex w/MA 140 (which is actually longer in distance than some other-mentioned I/US route duplexes (example: I-287 & NJ 17)).

[kphoger]

Is US 160 cheating?

Yes.  But its wife is OK with it.

[kphoger]

Texas loves to decommission and I may have missed something, but I don't find any US routes in Texas that don't duplex at some point. Regarding Interstates, I think I-610, I-635 and (arguably) I-345 may qualify.

How dare US-54 enter Texas twice!  Grrrr....

[Pete from Boston]

MA

I-84 (though it was once co-signed w/MA 15 many years back)
I-90
I-190
I-290
I-295
I-391
I-395

I would say 495 as well.  There's not really a time one is on both 495 and 140, even though 140 flanks 495 for a short stretch. 

It is my understanding that the primary premise of this thread is Interstates and US routes that have no other shared route along its corridor whatsoever within a state.  By that definition, I-495 in MA would not meet the OP's criteria due to its short duplex w/MA 140 (which is actually longer in distance than some other-mentioned I/US route duplexes (example: I-287 & NJ 17)).

I took it to mean no formal concurrency, i.e., if you're on one road you're also on the other.  I don't think this is the case with 140 and 495.

[NE2]

I-495/140 may be an official overlap, depending on how MassDOT handles ramps, but in reality 140 stays on the C/D roads.

[SectorZ]

I-495/140 may be an official overlap, depending on how MassDOT handles ramps, but in reality 140 stays on the C/D roads.

Agreed, in neither direction do you get onto 495 if you are staying on 140.

[empirestate]

PA (off the top of my head)

I-95 (forgot about the short segement that duplexes w/US 322)
I-176
I-276
I-283
I-476

You can add I-86 (if you don't count the segment that comes into PA that NY maintains and has NY-17 on it), & I-579 to that list.

Assuming that the two PA segments of I-86 are considered to be one highway/route; it can not be considered a route without a duplex.

Is I-86 designated in Bradford County yet?

[PHLBOS]

Agreed, in neither direction do you get onto mainline 495 if you are staying on 140.

FTFY.

IIRC, C/D roads are still considered to be part of its parent corridor alignment (in this case I-495).

[Bickendan]

Not sure about that... In ON 401's case, certainly, but B-30 in Barcelona are the C/D roads for AP-7, yet retains its own route number.

[Pete from Boston]

Well, the MassDOT roads layer says the road there is named "INTERSTATE 495 NB CD ROAD" and "INTERSTATE 495 SB CD ROAD," but that its route number is 140. 

Make of this what you will.

[OCGuy81]

Does I-15 in Arizona fly solo?

[kphoger]

Does I-15 in Arizona fly solo?

Yes.

[NE2]

Does US 160 in NM shit in the woods?

[wriddle082]

South Carolina has I-20, I-385, I-520, and I-526.

It seems that every US route in the state has a concurrency, which is easy to understand since there are so many of them.  No county in SC is served by fewer than two US routes.

The original poster said a few threads up that state roads don't count

OK, in that case, the short stretch of ALT US 221 from Chesnee to the NC state line is duplexed with SC 11, but not duplexed with any US routes.  So that makes exactly 1 for SC.