States that Disallow Route Number Duplication

[jemacedo9]

There is also US15 and NY15, though in that case, NY15 was formerly US15 (and used to extend from the current northern terminus of US15 until NYSDOT removed signage for NY15 along I-86/NY17 and I-390). Like US2, US15 is regarded as "15U".

NYSDOT Traffic Data Reports refer to it as 15U, but when I was on US 15 back in 2008, I saw reference markers that said 99I.

NY 15 is still currently signed along the parts of I-390, and all along the I-86/NY-17 multiplex.  Even the BGS heading onto I-390 North from I-86 West still has NY 15 on it.

Also, even though the traffic data reports use 15U, the reference markers we never updated, they still show "15".  The parts of US 15 that were newly constructed in Painted Post and at the PA line do have the 99I listing.

I agree with the earlier post about PA's duplication.  There were several, and although all were changed internally, the actual route number hasn't changed.

I-283 (SR 0283) and PA 283  (SR 0300)
I-380 (SR 0380) and PA 380  (SR 0400)
I-86 (SR 0086) and PA 86 (SR 0886)
I-99 (SR 0099) and PA 99 (either SR 0699 or SR 0399)

Also in PA, PA 29 and PA 97 exist in two separate parts of the state.  I believe PA 29 used to be connected in the 20's before the creation of US 309, now PA 309.  The southern PA 97 used to be US 140, and when decommissioned, was renumbered to match MD 97.  In both cases, SR 0029 and SR 0097 are used for both.

[kurumi]

CT had state route 95 as a continuation of I-95 for a few years in the southeast.
I-87 (now I-684) and CT 87 coexisted for about a year; CT was planning to change CT 87 to CT 287, but then NY changed I-87.
CT 190 and CT 93 were altered because of interstate designation conflicts in Massachusetts.

[Michael]

Also, even though the traffic data reports use 15U, the reference markers we never updated, they still show "15".  The parts of US 15 that were newly constructed in Painted Post and at the PA line do have the 99I listing.

I guess I should have been more specific.  I saw the 99I reference marker near the new I-86/US 15 interchange.  The portion of US 15 from Tioga, PA to Watson Creek Road was being built when I was last there.

[vdeane]

Must we seriously care how much I missed?

Given that you originally posted the one (and only) example of NYSDOT renumbering a route because of the interstate system and three later ones to say that NYSDOT once cared and no longer does, while Michael and I posted examples of routes that didn't get renumbered that date back to the same era as the NY 87 -> NY 812 renumbering, yes.

[74/171FAN]

VA mostly does not have route duplication outside of the SR's with the exception of state highway extensions(US 211/VA 211) and the infamous US 13 in Hampton Roads and VA 13 in Central Virginia

[hbelkins]

And US/VA 360, which actually intersect.

[NE2]

There's also primary SR 895 and secondary SR 895

[Quillz]

Stupid question, but CA routes that are separated by the Sierras and are near impossible to connect geographically, such as CA-190 and CA-168, are still funded as if they were a connected route, correct?

[corco]

Stupid question, but CA routes that are separated by the Sierras and are near impossible to connect geographically, such as CA-190 and CA-168, are still funded as if they were a connected route, correct?

I'm not quite sure what you mean by "funded," but they are codified as one highway

[WillWeaverRVA]

There's also primary SR 895 and secondary SR 895

Well, that situation isn't quite as bad since Henrico County doesn't have numbered secondary routes, and Chesterfield County's SR 895 is a rather short residential street (VA 895 only exists in Chesterfield County for about 0.2 mile or so) - not quite the same caliber as US/VA 360 and US/VA 211!

I-664 in Suffolk used to fall into this category when Suffolk still had numbered SRs, but it doesn't anymore.

[sandiaman]

Texas  actually   has  US 70,running E-W,  intersecting  a  N-S  highway :  another highway 70,  TX  70!

[SSOWorld]

Wisconsin, with one exception (I-39), does not use route number duplicates. And in that case, they could change the existing state highway to 139 or 239 without issue, but apparently determined nobody would confuse it for the interstate.

Technically there are two.  The other being I-794 and WIS 794, but it could be looked at as one.  The WI-794 part is not entirely controlled access.  (I-794 was slated to go down toward WIS 100 as a full freeway, but was trashed when the Nimbys (pre Nordquist the Freeway Killer) bitched.

WIS 39 is situated near I-39 but not close enough.   The east end is in New Glarus.  The Interstate version circles to the east of Janesville.  If they renumbered WIS 39, it would have to be a totally diferent number besides X39 - to account for the unlikely event that a freeway looping or spurring off I-39 got a 3di status.  Though the only candidate - if it were upgraded to Interstate standards - would be the Madison Beltline.

If the Interstate designation of US 41 truly were to be I-41, you'd have the I-74 syndrome (I-41 concurrent with US 41) as US 41 has historical roots at its northern terminus on the Keewenaw Peninsula in Michigan just east of Copper Harbor.

[PAHighways]

I-99 (SR 0099) and PA 99 (either SR 0699 or SR 0399)

SR 0699

I believe PA 29 used to be connected in the 20's before the creation of US 309, now PA 309.

It was one continuous route until 1966.

[yakra]

Maine initially did pretty well, renumbering state routes 201, 202, and 95, then cocked it all up by introducing I-195 in 1983.

[US71]

Arkansas used to, though we will some day have US 49 and I-49

[Eth]

Maryland has no duplication between state and US, but this doesn't extend to state/Interstate.  Fortunately, this doesn't really pose a problem, with perhaps one exception.

Georgia duplicates until it's blue in the face, including such bright ideas as US 27 intersecting SR 27 and SR 85 paralleling I-85 about 20 miles to the southeast for pretty much its entire length.

[wriddle082]

Georgia duplicates until it's blue in the face, including such bright ideas as US 27 intersecting SR 27 and SR 85 paralleling I-85 about 20 miles to the southeast for pretty much its entire length.

And let's not forget GA 20 intersecting I-20 over in Conyers!

Tennessee also duplicates route numbers between the three classifications, but for the most part avoids most major issues with duplicate numbers intersecting.  TN 81 comes close to I-81 near Fall Branch, TN 27 almost meets US 27 (they're connected by US 127), and TN 70 looks like it's on a heading to intersect US 70 until it crosses into North Carolina, where it becomes NC 208.  After further research, TN 74 actually DOES intersect US 74 in Cleveland, but US 74 is barely even recognized in TN since it's multiplexed (most of the time invisibly) with either US 64 or I-75 for its entire length.  And even though they don't come close to intersecting, both I-155 and TN 155 are freeways.

Funny story about the duplicate numbers: My father, who has been in sales longer than I've been alive and still makes trips to call on customers throughout Tennessee, doesn't understand the difference between TN 64 and US 64.  He knows that there are two of them (the one that connects Lewisburg to Shelbyville to Beechgrove, and the one that goes from Memphis to the foot of Monteagle Mountain), and he may even think that the one that goes through the Ocoee River Gorge is yet another one, but he doesn't understand the difference between the TN state route shield and the US route shield.  To him, they're both just "Highway 64".

[US71]

Missouri is a former. They renumbered MO 57 as MO 171 after I-57 was built and also renumbered Mo 55 and Mo 44... but now they have Mo 72/I-72; Mo 64/I-64; Mo 49/Future I-49

[FreewayDan]

US 287 intersects with MT 287 in Ennis, Montana.

[SidS1045]

Connecticut, Massachusetts, and RI all do not allow duplicate numbers.  There have been cases of multiple states having to renumbr a route because another state had to change a route number to avoid duplication (especially when the interstates were being built) and the neighboring state the route crossed into had to change their end. 

Mass has he only exception in that there is I-295 and a MA 295.  The reason these are allowed is they are both less than 5 miles long and are on opposite ends of the state. They both continue routes from neighboring states.  Actually, MA 295 used to just be signed as "To NY 295" at its Mass end for years.  Only recently was it signed as MA 295 in its own right. Always been a state maintained road as far as I know.

Not the only exception.  The duplication between US-3 and MA-3 is far older than the 295 one, and they're in the same general area, although they don't intersect.

[TheStranger]

Not the only exception.  The duplication between US-3 and MA-3 is far older than the 295 one, and they're in the same general area, although they don't intersect.

Isn't MA 3 a continuation of the US route?

[NE2]

Yes, they do intersect end-on.

[Jim]

Not the only exception.  The duplication between US-3 and MA-3 is far older than the 295 one, and they're in the same general area, although they don't intersect.

Isn't MA 3 a continuation of the US route?

According to the MassDOT shapefiles, the US3/MA3 designation change occurs along Memorial Drive in Cambridge when that route crosses MA2A/Mass Ave, in front of the MIT campus.

Anyone know the history of this?  Why not just keep the US 3 designation right down to US 6? 

[huskeroadgeek]

Arkansas used to, though we will some day have US 49 and I-49

Arkansas did briefly have I-540 and AR 540 though when the freeway N. of I-40 was just a stub and there still is I-440 and AR 440. I do know that they try to avoid it in other cases though-they even renumbered the short AR 371 from McRae to AR 267 in White County to a disjointed continuation of AR 13 when they added US 371 in the state.

[Alps]

Not the only exception.  The duplication between US-3 and MA-3 is far older than the 295 one, and they're in the same general area, although they don't intersect.

Isn't MA 3 a continuation of the US route?

According to the MassDOT shapefiles, the US3/MA3 designation change occurs along Memorial Drive in Cambridge when that route crosses MA2A/Mass Ave, in front of the MIT campus.

Anyone know the history of this?  Why not just keep the US 3 designation right down to US 6? 

US 3 always ended in Boston. I don't know if it was ever considered to extend further, but at least Mass DPW decided the number should go that far. Does anyone know if Mass. applied to FHWA to extend the route?